Public realtime data is scattered across exchange feeds, BGP collectors, certificate logs, social firehoses, weather alerts, transit feeds, court feeds, satellite-derived event feeds, and threat-intelligence sources. This atlas maps those surfaces and records the constraints that usually get missed: access, protocol, rate limits, terms, replay, coverage, and reuse.
This is not an awesome list. It is not a list of every WebSocket API. It tracks public-world data: observable external phenomena, public institutions, public markets, public networks, public safety, and public records.
Verification stance: a row is useful only if the transport, access model, legal boundary, and failure semantics are clear enough to build against. Public access does not imply permission to redistribute, resell, retain, train on, or derive commercial products from the data.
Included:
- public market data, betting odds, event markets, and prediction markets
- blockchain, mempool, public ledger, and onchain-event streams
- public social, publishing, wiki, and media activity
- BGP, DNS, certificates, routing, and internet-measurement data
- threat-intelligence, abuse, malware, phishing, and internet-exposure feeds
- aviation, maritime, rail, transit, traffic, and mobility feeds
- weather, seismic, fire, air-quality, environmental, satellite, and scientific feeds
- government records, public filings, legislation, courts, procurement, and emergency alerts
- sports, ticketing, marketplace, and public pricing signals
- open public protocols only when there is a meaningful public network, relay layer, or firehose
Excluded:
- generic pub/sub and streaming infrastructure
- self-hosted systems without a public network or public data surface
- app-state sync, backend state, application logs, cloud logs, observability streams, and internal telemetry
- customer-account webhooks and private SaaS events
- private Slack/Discord/Teams-style community events unless the data is explicitly public and policy-permitted
- ordinary polling APIs unless they are widely used as the de facto near-realtime public feed
Categories are organized by the phenomenon being observed, not by vendor industry or transport. Protocol still matters, but it is not the point: a WebSocket can be legally unusable, a webhook can be the canonical public alert channel, and a feed can be operationally realtime even if it is not an interactive stream.
Protocol values: WebSocket, SSE, Streaming HTTP, gRPC stream, GraphQL subscription, Webhook, Feed, Long polling, Mixed, Unclear / verify.
Access values: Public, Public auth required, Free account, Paid, Enterprise / partner, Research / academic, Invite-only, Restricted, Deprecated, Unclear.
Rate-limit values: exact official stream-specific limits when published; otherwise Not published, Plan-dependent, Endpoint-dependent, Connection-dependent, Subscription-dependent, Contact sales, or Unclear.
Notes standard: the notes column should answer: what would break a naive integration? Good notes mention replay, snapshots, dropped messages, coverage, sampling, licensing, redistribution, retention, deletion, venue entitlements, collector bias, or policy constraints. Generic praise is noise.
| Trap | Why it matters |
|---|---|
| Public docs ≠ public access | Some APIs require approval, KYC, paid plans, partner status, research approval, or exchange data entitlements. |
| Free access ≠ reuse rights | Many platforms permit access while restricting retention, redistribution, resale, training, or derived products. |
| Webhook ≠ WebSocket | Webhooks are event delivery. They make idempotency, retries, signatures, and replay part of the data model. |
| Polling ≠ streaming | Polling belongs only when the endpoint is the accepted near-realtime public feed for that domain. |
| Firehose ≠ complete population | Streams can be sampled, filtered, delayed, region-limited, or dependent on collector placement. |
| Realtime ≠ replayable | Live streams often need a separate historical API, snapshot API, archive, or backfill source. |
| Open protocol ≠ reliable feed | Relays, instances, nodes, hubs, and peers differ in retention, moderation, spam, availability, and policy. |
| Transport ≠ data quality | A clean WebSocket can still be incomplete, legally constrained, delayed, or operationally misleading. |
- Enterprise feeds can belong when they expose public-world data, but access should be marked
PaidorEnterprise / partner. - Webhook-only systems can belong when they deliver public-world events, not private account events.
- Unofficial APIs should usually be candidates, not catalog entries, unless the ecosystem treats them as the de facto public feed and the legal risk is clearly noted.
- High-name-recognition platforms should still be excluded if they have no public-data stream, no official docs, or only private account/event webhooks.
- Rows that say “not streaming” probably belong in candidates or expected exclusions, not in the main catalog.
| Type | Why excluded |
|---|---|
| Kafka, NATS, Redis, RabbitMQ, generic MQTT brokers | Infrastructure transports, not public data surfaces. |
| Firebase, Supabase, Hasura, Firestore listeners | App/backend state sync, not public external data. |
| Kubernetes, Docker, cloud logs, observability events | Internal infrastructure state, not public-world signal. |
| Generic SaaS webhooks | Usually customer-account events, not public external data. |
| Private chat/community events | Public-interest value is not enough if the data is private or policy-restricted. |
| Scraping-only targets | Public to view does not imply official API access or reuse rights. |
Tables are organized by the phenomenon being observed, not by protocol. A WebSocket order book, an SSE wiki-edit stream, and a CAP alert feed are all live public-data surfaces, but they fail in different ways.
Markets where live prices encode crowd beliefs about future events.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Polymarket | CLOB WebSocket / market data | WebSocket | Public auth required | Not published | Docs | Terms | Order book, trades, and market updates for prediction markets. | Interesting because prices are public belief traces, but CLOB and onchain settlement layers do not expose the same failure modes. |
| Kalshi | Market data WebSocket | WebSocket | Public auth required | Not published | Docs | Terms | Realtime exchange market data for regulated event contracts. | Regulatory status makes this structurally different from crypto prediction markets; redistribution and trading access should be treated separately. |
| Betfair Exchange | Exchange Stream API | Streaming HTTP | Public auth required | Not published | Docs | Terms | Streaming market and order data for betting exchange markets. | Exchange odds streams resemble financial order books, but market rules, latency, and jurisdictional restrictions are the hidden constraint. |
| Manifold Markets | Public API | Feed | Public | Not published | Docs | Terms | Near-realtime access to public prediction market objects and activity. | Good public belief data, but verify whether any stream exists before treating it as an event feed rather than polling. |
| Metaculus | Public questions API | Feed | Public | Not published | Docs | Terms | Public forecasting questions, predictions, and tournament data. | More useful as structured forecast history than as a true realtime stream. |
Public exchange feeds for trades, order books, tickers, funding, liquidations, and derivative markets.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Binance | Spot WebSocket Streams | WebSocket | Public | 5 incoming messages/sec; 300 connection attempts/5 min/IP | Docs | Terms | Live spot trades, depth, kline, ticker, and user-data streams. | Connections expire; consumers need reconnect and resubscribe logic rather than assuming an immortal socket. |
| Coinbase Exchange | WebSocket Feed | WebSocket | Public | Connection-dependent | Docs | Terms | Realtime public market data for orders and trades. | Full order book use requires snapshot plus message replay discipline; dropped sequence handling matters more than connection success. |
| Kraken | WebSocket API v2 | WebSocket | Public auth required | Not published | Docs | Terms | Spot market data, account data, and trading events. | Book checksums are useful because they expose drift that naive local book builders otherwise miss. |
| OKX | WebSocket API | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Market data, account, trading, and derivatives streams. | Instrument taxonomy is broad; stream consumers need product-aware normalization across spot, swaps, futures, and options. |
| Bybit | V5 WebSocket | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Public and private streams for spot, derivatives, options, tickers, trades, and books. | The transport is easy; the difficult part is normalizing category-specific payloads and maintenance windows. |
| Deribit | JSON-RPC over WebSocket | WebSocket | Public auth required | Not published | Docs | Terms | Options, futures, trades, order books, and instrument state. | Crypto options make this more valuable than simple spot feeds; implied-volatility consumers need instrument lifecycle handling. |
| BitMEX | WebSocket API | WebSocket | Public auth required | Not published | Docs | Terms | Realtime trades, order books, liquidations, instruments, and account tables. | The table/action model is convenient but can fool clients that do not handle partial, insert, update, and delete semantics correctly. |
| KuCoin | WebSocket Feed | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Realtime market and private account topics. | The bullet-token connection flow is an extra moving part; token expiry and endpoint selection are operational concerns. |
| Gate.io | WebSocket API v4 | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Spot, futures, options, delivery, margin, and account streams. | Product breadth creates schema drift; strategy code should not assume one exchange-wide event shape. |
| Gemini | Market Data WebSocket | WebSocket | Public | Not published | Docs | Terms | Market data event streams for Gemini symbols. | Good for cleaner market-data surfaces, but lower breadth means coverage should be checked before treating it as market-wide. |
| Bitstamp | WebSocket API v2 | WebSocket | Public | Not published | Docs | Terms | Live order book, trades, and ticker channels. | Public exchange feeds often omit legal clarity on downstream redistribution; public socket does not equal data license. |
| Crypto.com Exchange | WebSocket API | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Public market data and private user streams. | Authentication and request channels share the same transport family; separate public-data capture from trading automation. |
| dYdX | Indexer WebSocket API | WebSocket | Public | Not published | Docs | Terms | Order book, trades, markets, and account-oriented data from the dYdX stack. | Decentralized branding does not remove dependence on indexer availability and terms. |
| Hyperliquid | WebSocket API | WebSocket | Public | Not published | Docs | Terms | Realtime market, trade, book, and user data for Hyperliquid markets. | High-value for perp microstructure; verify terms and endpoint stability because unofficial wrappers are common. |
| Bitfinex | WebSocket API | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Ticker, trades, books, candles, status, and authenticated account streams. | Channel identifiers and pair naming conventions require careful normalization before cross-exchange joins. |
| HTX | WebSocket Market Data | WebSocket | Public | Connection-dependent | Docs | Terms | Realtime market data for spot and derivatives markets. | Branding and domain transitions make official-source verification more important than usual. |
| MEXC | WebSocket API | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Spot and contract market streams. | Useful for long-tail listings, but long-tail coverage increases symbol churn and delisting edge cases. |
| Bitget | WebSocket API | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Market data and account streams across spot and derivatives. | Topic naming and product-type separation are the practical integration burden. |
| Upbit | WebSocket Quotation API | WebSocket | Public | Connection-dependent | Docs | Terms | Realtime ticker, trade, and order-book data. | Regional market structure and fiat quote pairs can reveal local liquidity dynamics missed by global exchanges. |
Public-market data vendors, brokers, and exchange feeds. Access is often technically simple but legally gated.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Polygon.io | Market Data WebSockets | WebSocket | Paid | Plan-dependent | Docs | Terms | Realtime and delayed streams for stocks, options, forex, and crypto. | Redistribution rights and exchange entitlements matter more than the WebSocket mechanics. |
| Alpaca | Market Data Streaming | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Streaming US equities, options, and crypto market data depending on subscription. | Free-vs-paid access changes data quality and timeliness; do not benchmark strategies on one tier and deploy on another. |
| Finnhub | WebSocket Trades | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Realtime trades for stocks, forex, and crypto symbols. | Simple interface but symbol coverage, exchange provenance, and licensing are the real due-diligence items. |
| Twelve Data | WebSocket API | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Realtime price updates for supported financial instruments. | Good broad surface; confirm whether desired instruments are exchange-direct, consolidated, delayed, or synthetic. |
| Tiingo | IEX / Crypto WebSocket | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Realtime equity and crypto feeds depending on product. | IEX-only streams are not the same as consolidated tape; coverage affects conclusions about market state. |
| Databento | Live API | Streaming HTTP | Paid | Subscription-dependent | Docs | Terms | Live market data for futures, equities, options, and other venues. | Schema discipline is strong; licensing and venue entitlements still dominate downstream reuse. |
| Interactive Brokers | TWS / Client Portal streaming | Mixed | Free account | Connection-dependent | Docs | Terms | Broker-connected streaming market data, account, and order events. | The stream is tied to brokerage access and subscriptions, not an open public data product. |
| Tradovate | WebSocket API | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Futures market data, account, and trading streams. | Futures feeds inherit exchange licensing constraints even when the developer API is easy to access. |
| dxFeed | Market Data Services | Mixed | Paid | Contact sales | Docs | Terms | Realtime exchange and OTC market data feeds. | Enterprise market data is usually governed by venue-specific redistribution agreements, not just vendor terms. |
| Intrinio | Realtime Streaming APIs | WebSocket | Paid | Plan-dependent | Docs | Terms | Realtime equities, options, forex, crypto, and fundamentals products depending on plan. | Treat each data product separately; one vendor account does not imply one license boundary. |
| CME Group | Market Data Platform | Feed | Paid | Subscription-dependent | Docs | Terms | Exchange market data for futures and options. | This is the canonical example where the data license is the product; API transport is secondary. |
| Nasdaq | TotalView / market data products | Feed | Paid | Subscription-dependent | Docs | Terms | Depth and exchange market data products. | Direct exchange feeds are not normal APIs; commercial use usually requires explicit market-data agreements. |
Public ledger state, mempool activity, contract logs, and indexed onchain events.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Ethereum | eth_subscribe JSON-RPC |
WebSocket | Public | Provider-dependent | Docs | Not found | Subscriptions for new heads, logs, syncing, and pending transactions via supporting nodes. | Protocol access is open, but your view is only as good as the node/provider and mempool policy you connect to. |
| Infura | Ethereum subscription methods | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Hosted WebSocket subscriptions for Ethereum and other networks. | Provider-level rate limits, chain support, and archive access change what “same JSON-RPC” means operationally. |
| Alchemy | Subscription API | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Hosted WebSocket subscriptions and enhanced webhook-style streams. | Enhanced streams can be more useful than raw node subscriptions, but they introduce provider-specific semantics. |
| QuickNode | eth_subscribe and streams |
Mixed | Public auth required | Plan-dependent | Docs | Terms | WebSocket subscriptions and managed stream products across chains. | Do not assume mempool visibility is equivalent across providers; peering and filtering policies matter. |
| Solana | WebSocket RPC methods | WebSocket | Public | Provider-dependent | Docs | Not found | Account, program, slot, signature, logs, and root subscriptions. | High throughput makes backpressure and dropped subscription messages a first-order design concern. |
| Helius | WebSockets and enhanced transactions | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Solana transaction, account, and enhanced event streams. | Enhanced parsing saves work but makes your downstream schema dependent on Helius interpretation. |
| Solana Yellowstone | Yellowstone gRPC | gRPC stream | Public auth required | Provider-dependent | Docs | Not found | High-throughput Solana Geyser plugin gRPC streams. | Valuable for serious Solana monitoring, but access is usually mediated by providers or your own validator infrastructure. |
| Blocknative | Mempool API | WebSocket | Paid | Plan-dependent | Docs | Terms | Realtime mempool transaction events and transaction monitoring. | Mempool data is vantage-point data; absence from a feed does not imply absence from the network. |
| Tenderly | Alerts / Web3 Actions | Webhook | Public auth required | Plan-dependent | Docs | Terms | Event-driven contract, transaction, and alert notifications. | Useful for operational monitoring, less suitable as a neutral public firehose unless configured carefully. |
| Moralis | Streams API | Webhook | Public auth required | Plan-dependent | Docs | Terms | Webhook streams for wallet, contract, and onchain events. | Convenient high-level stream, but event interpretation and coverage are vendor-mediated. |
| OpenSea | Stream API | WebSocket | Public auth required | Plan-dependent | Docs | Terms | Realtime NFT marketplace events such as listings, offers, and sales. | Marketplace events are not the full NFT state space; chain events and marketplace policy changes diverge. |
| Mempool.space | WebSocket API | WebSocket | Public | Not published | Docs | Not found | Bitcoin blocks, mempool, and transaction updates. | Excellent public surface for Bitcoin state, but node vantage point and mempool policy shape what appears “live.” |
| Bitcoin Core | ZMQ notifications | Feed | Public | Operator-dependent | Docs | Terms | Block and transaction notifications from a Bitcoin node. | Public protocol primitive, not a hosted feed; completeness depends on your node and network connectivity. |
| Flashbots | MEV-Share events | SSE | Public | Not published | Docs | Terms | Event stream for MEV-Share pending transaction hints. | The feed is intentionally partial; privacy design means missing fields are a feature, not a bug. |
| bloXroute | Blockchain distribution network streams | Mixed | Paid | Plan-dependent | Docs | Terms | Low-latency blockchain transaction and block streams. | Latency advantage is the product; evaluate geography, peering, and ethical constraints before use. |
Streams of public posts, edits, channels, social graph events, and protocol-level activity.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| X | Filtered Stream | Streaming HTTP | Paid | Plan-dependent | Docs | Terms | Near-realtime public posts matching filter rules. | Access and policy are the constraint; the technical stream is simple compared with redistribution, retention, and plan limits. |
| Mastodon | Streaming API | WebSocket | Public auth required | Instance-dependent | Docs | Not found | Instance-local, federated, hashtag, and user streams depending on token and instance. | Federation means no single stream is the whole network; instance policy and federation topology define coverage. |
| Bluesky | Jetstream | WebSocket | Public | Not published | Docs | Terms | Simplified JSON stream of public AT Protocol events. | Jetstream is easier than raw firehose but still inherits relay coverage and cursor semantics. |
| AT Protocol | com.atproto.sync.subscribeRepos |
Streaming HTTP | Public auth required | Not published | Docs | Terms | Repository event firehose for AT Protocol updates. | This is closer to replication infrastructure than a social API; consumers need CAR/MST literacy or a simplification layer. |
| Nostr | Relay protocol | WebSocket | Open public network | Relay-dependent | Docs | Not found | Public relay subscriptions for signed events. | Open protocol does not mean uniform retention, moderation, anti-spam, or replay guarantees. |
| Farcaster | Hubble event stream | gRPC stream | Public | Node-dependent | Docs | Terms | Protocol events from Farcaster hubs. | Hub replication gives a cleaner event model than many social APIs, but API stability follows protocol evolution. |
| Wikimedia | EventStreams | SSE | Public | Not published | Docs | Terms | Continuous SSE streams of edits, page changes, and other Wikimedia events. | One of the cleanest public civic knowledge streams; event stream is not the same as durable history. |
| Hacker News | Firebase API | Feed | Public | Not published | Docs | Terms | Near-realtime item, user, and max-item data via Firebase endpoints. | Not a formal firehose, but max-item polling gives a practical near-realtime public-content surface. |
| Telegram | Bot API updates | Long polling | Public auth required | Endpoint-dependent | Docs | Terms | Updates for bots, including public channel contexts where the bot has access. | This is not a public Telegram firehose; access is scoped by bot membership and platform policy. |
| Twitch | EventSub WebSocket | WebSocket | Public auth required | Subscription-dependent | Docs | Terms | Realtime channel, stream, and interaction events. | Useful public-interest data is channel-scoped; broad monitoring requires explicit subscriptions and authorization. |
| Twitch | IRC over WebSocket | WebSocket | Public auth required | Connection-dependent | Docs | Terms | Live chat messages and IRC-style channel events. | Chat is often the most granular public reaction stream; moderation deletions and rate limits affect research conclusions. |
| YouTube | Live Chat API | Long polling | Public auth required | Quota-dependent | Docs | Terms | Live chat messages for YouTube broadcasts. | The official surface is polling-oriented; calling it streaming hides quota and freshness constraints. |
| YouTube | WebSub push notifications | Webhook | Public auth required | Not published | Docs | Terms | Push notifications for channel activity such as uploads. | Good for public publishing events, not live video content or chat firehose. |
| Matrix | Public room sync | Long polling | Public auth required | Server-dependent | Docs | Not found | Room timeline and state updates for rooms the user can access. | Federation and room membership make this a scoped public-room feed, not a global Matrix stream. |
| Lemmy | Federated community APIs | Feed | Public | Instance-dependent | Docs | Not found | Public posts, comments, communities, and federation-exposed activity. | ActivityPub federation means coverage is instance-vantage dependent. |
Public publishing and knowledge feeds that are near-realtime enough for monitoring.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| GDELT | GDELT 2.0 event feeds | Feed | Public | Not published | Docs | Terms | Global news event, mention, and document feeds updated frequently. | High breadth but noisy extraction; downstream users must model media bias and duplicate syndication. |
| Event Registry | News API | Feed | Public auth required | Plan-dependent | Docs | Terms | News, events, topics, and article streams from global media. | A semantic news index is not raw publication data; clustering and extraction choices shape the feed. |
| NewsAPI | Everything / top headlines | Feed | Public auth required | Plan-dependent | Docs | Terms | Near-realtime article metadata from many news sources. | Often useful for discovery, but licensing may restrict storing or displaying full content. |
| WebSub | W3C WebSub protocol | Webhook | Open public protocol | Hub-dependent | Docs | Not found | Pub/sub delivery for feed topic updates through hubs. | The protocol is simple; reliability and retention depend entirely on publisher and hub behavior. |
| RSSCloud | RSSCloud protocol | Webhook | Open public protocol | Hub-dependent | Docs | Not found | Push notification protocol for RSS feed updates. | Older and less fashionable than WebSub, but still relevant to feed-native publishing systems. |
| Crossref | Event Data | Feed | Public | Not published | Docs | Terms | Scholarly-event traces such as links, references, and social mentions. | Good for knowledge-diffusion signals, not a complete social or citation graph. |
| arXiv | Atom feeds / API | Feed | Public | Not published | Docs | Terms | Near-realtime metadata for new and updated preprints. | Feed timing follows submission/release workflows, not continuous publication. |
| bioRxiv / medRxiv | Content feeds | Feed | Public | Not published | Docs | Terms | Preprint metadata and article feeds. | Useful early science signal, but withdrawal, screening, and versioning semantics matter. |
| Internet Archive | Metadata APIs | Feed | Public | Not published | Docs | Terms | Public archive item metadata and search surfaces. | Near-realtime discovery is not guaranteed; archive ingestion lag varies by collection. |
| Podcast Index | API | Feed | Public auth required | Not published | Docs | Terms | Podcast feed, episode, and index data. | Podcast feeds are decentralized and timing depends on publisher RSS updates and crawler cadence. |
Feeds that expose internet-scale routing, naming, certificate, and measurement state.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| RIPE NCC | RIS Live | WebSocket | Public | Not published | Docs | Terms | Realtime BGP announcements and withdrawals from RIS collectors. | Collector and peer coverage determine what events are visible; this is not a global omniscient route feed. |
| CAIDA | BGPStream | Feed | Public | Not published | Docs | Terms | Framework and data access for live and historical BGP data. | Research-grade routing data requires understanding collectors, MRT timing, and outage gaps. |
| RouteViews | BGP update archives | Feed | Public | Not published | Docs | Terms | BGP table dumps and update feeds from RouteViews collectors. | More archive/feed than interactive stream; still essential for public routing reconstruction. |
| RIPE Atlas | Streaming measurement results | Streaming HTTP | Public auth required | Not published | Docs | Terms | Streaming results for internet measurements from RIPE Atlas probes. | Probe distribution and measurement design matter more than API latency. |
| CertStream | Certificate transparency stream | WebSocket | Public | Not published | Docs | Not found | Live stream of certificates observed from Certificate Transparency logs. | New certificates can reveal staging or phishing infrastructure before DNS, crawling, or blocklists catch up. |
| Certificate Transparency | CT log APIs | Feed | Public | Not published | Docs | Not found | Append-only public certificate log data. | Logs are public but monitoring completeness depends on which logs you track and how quickly you poll or stream. |
| crt.sh | Certificate search | Feed | Public | Not published | Docs | Not found | Public search over certificate transparency data. | Useful discovery surface, but not a formal low-latency stream interface. |
| urlscan.io | Search and result APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Recent URL scan submissions, results, domains, and artifacts. | Public submissions can leak attacker and defender activity; privacy status of scans is part of the data model. |
| Cloudflare Radar | Radar API | Feed | Public auth required | Not published | Docs | Terms | Internet traffic, DNS, routing, attack, and outage indicators. | Great aggregate signal; not a raw event firehose and not a substitute for packet or BGP telemetry. |
| PeeringDB | API | Feed | Public | Not published | Docs | Terms | Network, facility, exchange, and peering metadata. | Slow-changing but high-value context for interpreting routing and outage feeds. |
| SecurityTrails | DNS and domain API | Feed | Paid | Plan-dependent | Docs | Terms | DNS, domain, and historical infrastructure intelligence. | Passive DNS products are about coverage and licensing, not just API freshness. |
| WhoisXML API | Domain and DNS feeds | Feed | Paid | Plan-dependent | Docs | Terms | Domain registration, DNS, WHOIS, and threat-intel data products. | Domain-data feeds often combine public records with proprietary collection; redistribution should be checked. |
Public or commercial feeds of scanning, abuse, malware, phishing, and reputation signals.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Shodan | Streaming API | Streaming HTTP | Paid | Plan-dependent | Docs | Terms | Realtime stream of banners and scan observations collected by Shodan. | This is internet-exposure telemetry from Shodan’s vantage point, not ground truth about all exposed services. |
| GreyNoise | GNQL / intelligence APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Internet scanner and noise classification data. | Useful for separating opportunistic background noise from targeted activity, but classifications age and should be rechecked. |
| VirusTotal | Intelligence APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | File, URL, domain, IP, and submission intelligence. | Strong enrichment source; terms and privacy rules are unusually important because submitted artifacts may contain sensitive data. |
| URLhaus | API and feeds | Feed | Public | Not published | Docs | Terms | Malware URL intelligence from abuse.ch. | High-signal public abuse data, but takedown timing and reporter bias shape apparent campaign timelines. |
| MalwareBazaar | API | Feed | Public | Not published | Docs | Terms | Malware sample metadata and intelligence. | Sample availability is not prevalence; use as discovery/enrichment, not population statistics. |
| AbuseIPDB | API | Feed | Public auth required | Plan-dependent | Docs | Terms | Community-reported abusive IP activity. | Crowdsourced reporting is useful but can encode defender deployment patterns and false positives. |
| Spamhaus | DROP and reputation feeds | Feed | Public / Paid | Subscription-dependent | Docs | Terms | IP and domain reputation blocklists and data products. | Access may be public for limited use but commercial redistribution is a separate question. |
| AlienVault OTX | Pulse and indicator API | Feed | Public auth required | Not published | Docs | Terms | Community threat-intelligence pulses and indicators. | Community IOCs are fast but uneven; confidence and decay handling are mandatory. |
| PhishTank | Phishing feed/API | Feed | Public auth required | Not published | Docs | Terms | Community phishing URL submissions and verification status. | Verification status is part of the signal; raw submissions alone can be noisy or adversarial. |
| OpenPhish | Phishing feeds | Feed | Public / Paid | Plan-dependent | Docs | Terms | Phishing URL feeds and intelligence products. | Free feeds may be delayed or limited; commercial terms govern production use. |
| ThreatFox | API | Feed | Public | Not published | Docs | Terms | IOCs associated with malware families. | Family attribution is useful but should not be treated as final without corroboration. |
| Feodo Tracker | Botnet C2 feeds | Feed | Public | Not published | Docs | Terms | Botnet command-and-control blocklists. | Excellent operational feed; absence does not imply clean infrastructure because C2 visibility is campaign-dependent. |
| SSLBL | SSL certificate blocklist | Feed | Public | Not published | Docs | Terms | Malicious SSL certificate fingerprints and related indicators. | Pairs well with CT streams; certificate reuse can reveal infrastructure clusters. |
| DShield / SANS ISC | Internet Storm Center feeds | Feed | Public | Not published | Docs | Terms | Attack, scanning, port, and diary-derived security data. | Sensor population bias is central; interpret trends as seen by the network, not the whole internet. |
| MISP | Feed format and communities | Feed | Public / Restricted | Instance-dependent | Docs | Not found | Threat-intelligence event feeds from MISP instances and communities. | The software is open, but each community’s sharing group and trust model define what data exists. |
Vehicle, vessel, aircraft, traffic, and public-transport feeds.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| GTFS Realtime | Realtime feed specification | Feed | Public | Agency-dependent | Docs | Not found | Transit vehicle positions, trip updates, and service alerts. | Always interpret against the static GTFS feed; realtime IDs without schedule context are easy to misread. |
| OpenSky Network | Live states API | Feed | Public auth required | Rate-limited | Docs | Terms | Live aircraft state vectors and flight data. | ADS-B coverage depends on receiver geography and data-sharing policy, not just aircraft presence. |
| ADS-B Exchange | Aircraft data API | Feed | Paid | Plan-dependent | Docs | Terms | Live aircraft tracking and ADS-B-derived data. | Aircraft tracking feeds have strong policy and safety sensitivities around blocking, military, and private aircraft. |
| AISStream | AIS WebSocket stream | WebSocket | Free account | Not published | Docs | Terms | Realtime AIS vessel position messages over WebSocket. | AIS is self-reported vessel telemetry; spoofing, gaps, and satellite/terrestrial coverage differences matter. |
| FlightAware | Firehose / AeroAPI | Mixed | Enterprise / partner | Contact sales | Docs | Terms | Commercial aviation data feeds and APIs. | The feed is valuable because it combines sources; source fusion also obscures provenance unless licensed terms specify it. |
| MarineTraffic | AIS API services | Feed | Paid | Plan-dependent | Docs | Terms | Vessel positions, port calls, voyages, and AIS-derived data. | AIS commercial feeds are coverage products; identical MMSI queries can differ materially across vendors. |
| Spire Maritime | Maritime AIS APIs | Feed | Enterprise / partner | Contact sales | Docs | Terms | Satellite and terrestrial AIS maritime data. | Satellite AIS reduces ocean blind spots but introduces latency, collision, and decoding tradeoffs. |
| Transport for London | Unified API | Feed | Public | Not published | Docs | Terms | Live arrivals, disruptions, bike, road, and transit status data. | A strong model for public transport APIs because terms and data-product boundaries are explicit. |
| MTA | Realtime transit feeds | Feed | Public auth required | Agency-dependent | Docs | Terms | Subway, bus, railroad, and service-alert feeds. | GTFS-rt consumers need route-specific quirks and agency-specific service-alert interpretation. |
| Network Rail | Open data feeds | Feed | Public auth required | Not published | Docs | Terms | UK rail train movement and schedule feeds. | Operational rail messages are not passenger-friendly by default; mapping to service meaning takes domain work. |
| TransportAPI | UK transport APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | UK public transport, roads, and journey data. | Aggregator convenience trades off against source-level clarity and licensing granularity. |
| Waze for Cities | Traffic data exchange | Feed | Partner | Contact sales | Docs | Terms | Traffic, incident, and road-closure data for public-sector partners. | High civic value but not open self-serve; access is governed by partnership. |
Environmental feeds where timeliness and provenance change operational value.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| National Weather Service | Alerts / API | Feed | Public | Not published | Docs | Terms | Weather alerts, forecasts, observations, and gridpoint data. | Official public source for US weather alerts; clients should handle CAP semantics and office-specific products. |
| NWS | CAP alert feeds | Feed | Public | Not published | Docs | Terms | Common Alerting Protocol feeds for US weather alerts. | CAP is an alert lifecycle format; updates, cancellations, and polygons matter as much as headline text. |
| NOAA CO-OPS | Tides and currents API | Feed | Public | Not published | Docs | Terms | Water levels, tides, currents, predictions, and meteorological observations. | Station quality and datum handling are the subtle failure modes. |
| NDBC | Buoy data feeds | Feed | Public | Not published | Docs | Terms | Realtime buoy and marine weather observations. | Sensor outages and station maintenance produce gaps that can be misread as environmental change. |
| USGS | Earthquake feeds | Feed | Public | Not published | Docs | Terms | Near-realtime earthquake event feeds. | Preliminary magnitudes and locations change; consumers must handle revisions and deletions. |
| EMSC | Seismic feeds | Feed | Public | Not published | Docs | Terms | European-Mediterranean earthquake event data. | Different seismic networks can disagree early; multi-feed reconciliation is normal. |
| NASA FIRMS | Fire Information API | Feed | Public auth required | Not published | Docs | Terms | Near-real-time active fire and thermal anomaly data. | Satellite overpass timing means “near real time” is orbital, not continuous. |
| NASA EONET | Earth Observatory Natural Event Tracker | Feed | Public | Not published | Docs | Terms | Natural event metadata for storms, fires, volcanoes, sea ice, and more. | Good event index, not a sensor firehose; link to source products for operational use. |
| OpenAQ | Air quality API | Feed | Public | Not published | Docs | Terms | Aggregated air-quality measurements from public sources. | Great for coverage, but stations, averaging windows, and pollutant definitions vary across jurisdictions. |
| AirNow | AirNow API | Feed | Public auth required | Not published | Docs | Terms | US air-quality observations and forecasts. | AQI abstraction hides pollutant-specific dynamics; use raw observations when possible. |
| PurpleAir | Sensor API | Feed | Public auth required | Plan-dependent | Docs | Terms | Low-cost air-quality sensor readings. | Dense community sensors are powerful but calibration, indoor/outdoor status, and sensor aging are key. |
| WAQI | Air Quality API | Feed | Public auth required | Not published | Docs | Terms | Global air-quality station data and AQI feeds. | Convenient global index, but source station policies and AQI formulas vary. |
| OpenWeather | Weather alerts / APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Weather, alerts, and forecast data products. | Commercial aggregators smooth source diversity; check source attribution and redistribution rights. |
| Tomorrow.io | Realtime weather APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Weather observations, forecasts, alerts, and timeline data. | Useful for product integration; public-interest reuse depends on plan and licensing terms. |
| RainViewer | Radar API | Feed | Public | Not published | Docs | Terms | Weather radar map tiles and nowcast data. | Radar tiles are excellent for visualization, weaker for quantitative meteorology unless calibrated. |
Official public-record and alert surfaces where update semantics matter.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| SEC | EDGAR submissions / feeds | Feed | Public | Rate-limited | Docs | Terms | Company filings, submissions, and disclosure data. | Timeliness is valuable, but fair-access rules and user-agent requirements must be respected. |
| Federal Register | API | Feed | Public | Not published | Docs | Terms | Federal rules, notices, and presidential documents. | Official publication timing makes this a strong public-policy event surface. |
| Congress.gov | API | Feed | Public auth required | Rate-limited | Docs | Terms | Bills, amendments, members, summaries, and legislative activity. | Legislative status is event-like but updates follow publication workflows and may lag floor activity. |
| OpenFEC | API | Feed | Public auth required | Rate-limited | Docs | Terms | Campaign finance filings, committees, candidates, and receipts. | Disclosure timing and amendment behavior are essential; latest filing is not necessarily final truth. |
| CourtListener | API / RECAP | Feed | Public auth required | Rate-limited | Docs | Terms | Opinions, dockets, oral arguments, judges, and RECAP documents. | Court data is uneven by jurisdiction and source; docket updates can be delayed or incomplete. |
| UK Companies House | Streaming API | Streaming HTTP | Public auth required | Not published | Docs | Terms | Streaming company filing-history and officer update events. | A rare official corporate-registry stream; reconnect and resume behavior matters for completeness. |
| OpenCorporates | API | Feed | Public auth required | Plan-dependent | Docs | Terms | Company, officer, and corporate-network data. | Aggregated corporate data is high-value but licensing and provenance should be examined per jurisdiction. |
| EU TED | Tenders Electronic Daily API | Feed | Public | Not published | Docs | Terms | European public procurement notices. | Procurement feeds are slow-moving but economically meaningful public signals. |
| SAM.gov | Entity and opportunity APIs | Feed | Public auth required | Rate-limited | Docs | Terms | US federal opportunities, entity registration, and assistance listings. | Good public signal, but agency posting practices and amendments complicate event semantics. |
| FEMA IPAWS | Public alerts / CAP | Feed | Public | Not published | Docs | Terms | Emergency alerts and warning messages via CAP-compatible systems. | Public-safety feeds require lifecycle handling; expired, updated, and cancelled alerts are not duplicates. |
Public science and earth-observation sources with frequent updates or event-driven value.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| NASA CMR | Common Metadata Repository API | Feed | Public | Not published | Docs | Terms | Earth science collection and granule metadata. | Good discovery layer; actual freshness depends on mission ingest and product latency. |
| NOAA GOES | Satellite data access | Feed | Public | Not published | Docs | Terms | GOES satellite imagery and products through public data channels. | Near-real-time satellite data is product-specific; do not generalize latency across bands and derived products. |
| Copernicus Data Space | APIs | Feed | Public auth required | Not published | Docs | Terms | Sentinel and Copernicus earth-observation product discovery and access. | Search API is not the same as low-latency tasking; product generation delays dominate. |
| Sentinel Hub | APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Satellite imagery processing and data-access APIs. | Powerful for derived products, but computation and source-data licensing are separate boundaries. |
| USGS | Water Services | Feed | Public | Not published | Docs | Terms | Realtime and historical streamflow, groundwater, and water-quality observations. | Gauge outages and provisional data flags are crucial for operational use. |
| GBIF | Occurrence API | Feed | Public | Not published | Docs | Terms | Biodiversity occurrence records and datasets. | Not realtime in the strict sense; useful as a public observation stream only at ingest cadence. |
| iNaturalist | API | Feed | Public | Not published | Docs | Terms | Public biodiversity observations and identifications. | Human observation and identification lag shape the signal more than API latency. |
| eBird | API | Feed | Public auth required | Rate-limited | Docs | Terms | Recent bird observations and regional checklists. | Observation bias is extreme but useful; absence often means no observer, not no bird. |
| Movebank | Data repository APIs | Feed | Public auth required | Dataset-dependent | Docs | Terms | Animal movement data from public and permissioned studies. | Public/private dataset boundaries vary by study; treat access as dataset-specific. |
| Global Fishing Watch | APIs | Feed | Public auth required | Plan-dependent | Docs | Terms | Fishing activity, vessel presence, and maritime analytics. | Derived behavioral classifications are not raw AIS; model assumptions become data assumptions. |
Live scores, play-by-play, odds, and sports-event feeds.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| Sportradar | Sports APIs | Feed | Paid | Subscription-dependent | Docs | Terms | Live scores, statistics, schedules, and odds products. | Official sports data is heavily licensed; coverage and permitted use vary by league and product. |
| Stats Perform / Opta | Sports data feeds | Feed | Enterprise / partner | Contact sales | Docs | Terms | Live sports event, performance, and editorial data. | The business model is rights and data collection; API access is downstream of licensing. |
| Genius Sports | Sports data products | Feed | Enterprise / partner | Contact sales | Docs | Terms | Official live sports data and betting services. | Official designation may matter more than latency when bookmakers or media require licensed data. |
| The Odds API | Odds API | Feed | Public auth required | Plan-dependent | Docs | Terms | Odds across bookmakers and sports. | Odds aggregation is inherently source-normalized; sportsbook availability and region filters affect conclusions. |
| SportsDataIO | Sports APIs | Feed | Paid | Subscription-dependent | Docs | Terms | Scores, fantasy, odds, projections, and stats data. | Fine for product use; check whether live data latency and league rights match the application. |
| API-Football | Football API | Feed | Public auth required | Plan-dependent | Docs | Terms | Fixtures, live scores, standings, events, and odds for football. | Broad global coverage often trades off against source provenance and exact event timing. |
| football-data.org | Football data API | Feed | Public auth required | Plan-dependent | Docs | Terms | Football fixtures, results, standings, and match data. | Better as structured match data than high-frequency live event feed. |
| MLB | Stats API | Feed | Public | Not published | Docs | Terms | Baseball schedules, game state, play-by-play, and statistics. | Unofficially relied on by many clients; verify licensing before redistribution. |
| NHL | Web API | Feed | Public | Not published | Docs | Terms | Hockey schedules, boxscores, standings, and game state. | Docs are community-maintained more than official; keep in candidates if strict official-doc policy is required. |
| Pinnacle | Odds API | Feed | Public auth required | Plan-dependent | Docs | Terms | Sports odds and betting market data for authenticated users. | Odds movement is valuable public-market signal, but account/geography restrictions are material. |
Public-facing marketplace, ticketing, crypto-pricing, and event-commerce surfaces.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| CoinGecko | API | Feed | Public auth required | Plan-dependent | Docs | Terms | Crypto asset prices, market data, exchanges, NFTs, and metadata. | Great breadth, but aggregation methodology and exchange coverage affect derived market signals. |
| CoinMarketCap | API | Feed | Public auth required | Plan-dependent | Docs | Terms | Crypto prices, listings, market caps, and exchange data. | Market-cap rankings are derived products; methodology matters for longitudinal analysis. |
| DefiLlama | API | Feed | Public | Not published | Docs | Terms | DeFi TVL, yields, fees, volumes, stablecoins, and protocol data. | Useful open aggregator, but protocol adapters encode assumptions that should be audited for serious work. |
| DEX Screener | API | Feed | Public | Rate-limited | Docs | Terms | DEX pairs, token profiles, prices, and liquidity data. | Fast long-tail token discovery, but spam tokens and pool manipulation are endemic. |
| Birdeye | API | Feed | Public auth required | Plan-dependent | Docs | Terms | Onchain token, price, trade, and liquidity data. | Useful for Solana and multichain markets; derived labels and aggregation should be validated. |
| Ticketmaster | Discovery API | Feed | Public auth required | Rate-limited | Docs | Terms | Public event, venue, attraction, and ticketing metadata. | Public events are good demand signals, but inventory and price availability are not equivalent. |
| SeatGeek | Platform API | Feed | Public auth required | Rate-limited | Docs | Terms | Events, performers, venues, and ticket listings. | Marketplace prices reflect listed supply, not necessarily clearing prices. |
| Eventbrite | API | Feed | Public auth required | Rate-limited | Docs | Terms | Public events, organizers, venues, and ticketing metadata. | Event creation is a local economic signal but spam, cancelled events, and private events complicate interpretation. |
| eBay | Buy Browse API | Feed | Public auth required | Rate-limited | Docs | Terms | Public marketplace item search and listing metadata. | Search results are ranked and policy-mediated; not a neutral complete listing stream. |
| Steam | Community Market APIs | Feed | Public auth required | Endpoint-dependent | Docs | Terms | Market item price and listing surfaces for supported items. | Public pricing is shaped by market restrictions, fees, and game-specific inventory semantics. |
Protocols included only where there is a meaningful public network, relay layer, or public feed surface.
| Platform | API / Stream | Protocol | Access | Rate limits | Docs | Terms | Description | Notes |
|---|---|---|---|---|---|---|---|---|
| ActivityPub | Federated social protocol | Webhook | Open public protocol | Server-dependent | Docs | Not found | Federated inbox/outbox activity for public social objects. | There is no global ActivityPub firehose; every view is instance and federation-topology dependent. |
| AT Protocol | Repo sync / firehose | Streaming HTTP | Open public protocol | Relay-dependent | Docs | Terms | Repository synchronization and public event streams for AT Protocol networks. | Designed for replication; consumers must decide whether to use raw sync or a simplified relay like Jetstream. |
| Nostr | Relay subscriptions | WebSocket | Open public protocol | Relay-dependent | Docs | Not found | Signed event relay subscriptions for public notes and other event kinds. | Relay choice is the data source; there is no canonical complete network. |
| WebSub | Feed update push protocol | Webhook | Open public protocol | Hub-dependent | Docs | Not found | Push delivery for topic updates through hubs. | Useful public publishing primitive, but often invisible behind platform-specific implementations. |
| BitTorrent DHT | DHT queries / crawls | Feed | Open public network | Operator-dependent | Docs | Not found | Distributed hash table metadata and peer-discovery signals. | Public network telemetry can reveal content popularity, but crawling ethics and IP privacy matter. |
| IPFS | PubSub / DHT | Mixed | Open public network | Operator-dependent | Docs | Not found | Public-network pubsub and routing signals in IPFS contexts. | PubSub is not global by default; topic discovery and persistence are the hard parts. |
| Lightning Network | Gossip protocol | Feed | Open public network | Node-dependent | Docs | Not found | Public channel graph and routing gossip. | Gossip exposes public channel topology, not private channel liquidity or payment flow. |
| Matrix | Federated room sync | Long polling | Open public protocol | Server-dependent | Docs | Not found | Event sync for accessible public rooms. | Membership and homeserver perspective define the observed stream. |
| RSSCloud | RSS update notifications | Webhook | Open public protocol | Hub-dependent | Docs | Not found | Push notifications for RSS feed changes. | Still useful where publishing ecosystems expose native feeds rather than platform APIs. |
| IRC | Public channels | Native socket | Open public network | Network-dependent | Docs | Not found | Live messages and events in public IRC channels. | Old but still a public social stream; netsplits and channel policy are the failure modes. |
These are plausible public-data surfaces that should not be promoted into the main catalog until official docs, terms, access, and realtime semantics are checked.
| Candidate | Possible surface | Why it might belong | Missing verification |
|---|---|---|---|
| Smarkets | Betting exchange API / streaming | Event-market odds and order book data may be public-interest market signal. | Official stream docs, terms, and public access. |
| PredictIt | Market API / feeds | Political prediction market prices are public belief signals. | Whether an official realtime or near-realtime API exists. |
| Insight Prediction | Prediction-market API | Crypto-native prediction markets may expose public market streams. | Official docs and legal terms. |
| Hedgehog Markets | Prediction-market data | Prediction-market prices may expose public event beliefs. | Whether a maintained public API exists. |
| Backpack Exchange | Exchange WebSocket | Crypto market microstructure. | Official docs and terms stability. |
| Bullish | Market data API | Institutional crypto exchange market data. | Public stream access and licensing. |
| Bithumb | WebSocket market data | Korean crypto market data with regional liquidity signal. | English official docs and terms mapping. |
| WOO X | WebSocket API | Crypto exchange with market data streams. | Official docs, access, and rate limits. |
| AscendEX | WebSocket API | Crypto market streams. | Current docs and legal status. |
| Kraken Futures | Futures WebSocket | Crypto derivatives market data. | Separation from Kraken spot docs and terms. |
| LSEG / Refinitiv | Realtime data platform | Major financial market data feed. | Self-serve docs and licensing details. |
| Bloomberg B-PIPE | Realtime market data feed | Canonical enterprise market data surface. | Public docs, terms, and access model. |
| ICE Data Services | Realtime data feeds | Exchange and fixed-income market data. | Product-specific access and redistribution terms. |
| Cboe DataShop | Market data feeds | Options and equities market data. | Live stream docs and licensing. |
| CQG | Market data API | Futures market data and order routing. | Developer docs and public-data terms. |
| Rithmic | Market data feed | Futures depth and trading feeds. | Docs and redistribution rights. |
| Barchart | Market data APIs | Commodity, futures, equity, and news data. | Realtime access and terms. |
| Quodd | Market data APIs | US market data vendor. | Stream docs and legal constraints. |
| Xignite | Financial APIs | Financial market and reference data. | Realtime status and rate limits. |
| Goldsky | Blockchain subgraphs / streams | Onchain indexed event feeds. | Public data relevance and stream mechanics. |
| Reservoir | NFT market data API | NFT marketplace listings and sales. | Stream availability and redistribution terms. |
| SimpleHash | NFT API / webhooks | NFT ownership and metadata changes. | Public stream semantics and license. |
| Zapper | Onchain portfolio/data APIs | Public DeFi position data may be externally observable. | Public API access and whether stream exists. |
| Zerion | Wallet/onchain APIs | Public wallet and portfolio changes. | Whether access is public-data or account-product focused. |
| Nansen | Onchain intelligence APIs | Labeled public onchain activity. | API docs and terms. |
| Arkham | Onchain intelligence APIs | Entity-labeled chain data. | Official API docs, pricing, redistribution rights. |
| Chainbase | Onchain data APIs | Blockchain indexed public data. | Realtime stream support. |
| Tatum | Blockchain notifications | Onchain webhooks/streams. | Public-data scope and terms. |
| Blockchair | Blockchain data API | Multi-chain public ledger data. | Realtime or near-realtime status and limits. |
| Lens Protocol | Social graph events | Public social protocol activity. | Current firehose/event API docs. |
| Public API / firehose products | Public social content and discussion data. | Current official access after API policy changes and realtime surface. | |
| TikTok Research API | Public content research access | Public social video data has major public-interest value. | Realtime behavior, research eligibility, and terms. |
| Facebook Graph webhooks | Public Page / media updates | Public page activity can be public-interest data. | Policy-permitted public-data use and app review. |
| Instagram Graph webhooks | Public/business media updates | Public media and creator activity. | Eligibility and restrictions. |
| LinkedIn organization events | Public organization updates | Public corporate communications signal. | Official event/webhook docs and terms. |
| Product Hunt | Launch/product API | Public product-launch event feed. | Current API docs and realtime status. |
| PeerTube | Federated video activity | Public federated media events. | Current API and feed behavior. |
| Misskey / Firefish | Federated social streams | ActivityPub-compatible public social events. | Instance-level stream docs and network coverage. |
| Stack Exchange | API / websocket traces | Public Q&A events. | Official realtime surface versus polling. |
| MediaCloud | Media corpus feeds | News and media research data. | Current API availability and update cadence. |
| AYLIEN | News API / streams | Commercial news intelligence. | Realtime docs and terms. |
| Diffbot | Knowledge graph / crawl APIs | Public web content extraction. | Realtime/feed availability. |
| LexisNexis | News/data feeds | Enterprise public-record/news feeds. | Public docs and licensing. |
| Factiva | News feeds | Enterprise news signal. | Docs, terms, and API access. |
| OpenAlex | Works API | Scholarly graph updates. | Update cadence and feed semantics. |
| Semantic Scholar | Recommendations / paper API | Scholarly-publication signal. | Near-realtime update cadence and terms. |
| Common Crawl | Index updates | Public web corpus updates. | Timeliness and feed surface. |
| BGP.Tools | Routing data | Public routing observability. | API/stream availability and legal terms. |
| Hurricane Electric BGP | BGP toolkit | Routing visibility and prefix data. | Official API/stream status. |
| Isolario | BGP streaming/route collectors | BGP public telemetry. | Current public stream docs and access. |
| Kentik | Synthetic / network telemetry APIs | Internet performance and routing intelligence. | Public-data versus customer telemetry boundary. |
| ThousandEyes | Internet outage APIs | Public internet availability signal. | Public access and terms. |
| Catchpoint | Internet performance data | Public web performance signals. | Public feed availability. |
| OpenINTEL | DNS measurement data | Large-scale DNS measurement. | Access, update cadence, and terms. |
| DNS-OARC | DNS data feeds | DNS research telemetry. | Public feed eligibility and terms. |
| DomainTools | Domain intelligence feeds | Domain, DNS, and WHOIS intelligence. | Realtime feed docs and license. |
| Farsight DNSDB | Passive DNS API | Passive DNS intelligence. | Stream support and terms. |
| RiskIQ / PassiveTotal | Internet intelligence API | Passive DNS and infrastructure intelligence. | Current Microsoft product docs and access. |
| Censys | Search / ASM data | Internet-exposure intelligence. | Whether public streaming exists or only API/search. |
| Recorded Future | Threat intelligence feeds | Commercial threat intel. | Public docs, access, and data-use rights. |
| Flashpoint | Threat intel APIs | Threat actor and illicit community signals. | Public docs and terms. |
| Intel 471 | Threat intelligence APIs | Cybercrime intelligence. | Official API docs and access. |
| KELA | Dark-web intelligence APIs | Threat intelligence public-interest signal. | Docs and legal constraints. |
| Shadowserver | Network reports / feeds | Public-benefit security telemetry. | Realtime feed access and redistribution rules. |
| Team Cymru | Scout / threat feeds | Network and threat-intel signals. | Access and terms. |
| Hybrid Analysis | Malware analysis API | Sample and sandbox intelligence. | Current API status and terms. |
| ANY.RUN | Threat intel APIs | Interactive sandbox and public malware tasks. | Feed surface and licensing. |
| MalShare | Malware sample feed | Malware samples and metadata. | API reliability and terms. |
| PhishStats | Phishing statistics/feed | Phishing URL intelligence. | Official docs and usage terms. |
| ADSB.lol | Aircraft feed/API | Open aircraft tracking data. | Official docs, rate limits, and terms. |
| ADSB.fi | Aircraft feed/API | Aircraft tracking public data. | Official docs and redistribution policy. |
| Airplanes.live | Aircraft feed/API | ADS-B aircraft data. | API docs and terms. |
| Flightradar24 | Commercial flight data | Aviation tracking public-interest signal. | Enterprise feed docs and licensing. |
| Aviationstack | Flight API | Flight status and aviation data. | Realtime accuracy and license. |
| VesselFinder | AIS API | Vessel position data. | Official developer docs and terms. |
| exactEarth | Satellite AIS | Maritime vessel tracking. | Current product docs and access. |
| AISHub | AIS feed exchange | Maritime AIS data sharing. | Access rules and terms. |
| NOAA AIS | AIS datasets/feeds | Public vessel movement data. | Realtime availability. |
| OpenRailData UK | Rail feeds | Rail operations public data. | Current feed docs and terms. |
| MBTA | GTFS Realtime | Public transit live data. | Specific official docs and terms. |
| BART | Realtime API | Public transit live data. | Current docs and rate limits. |
| WMATA | Realtime API | Transit arrivals and service data. | Docs and terms. |
| SEPTA | Realtime feeds | Transit live operations. | Official terms and feed list. |
| CTA | Bus/train trackers | Transit live data. | Developer terms and limits. |
| Deutsche Bahn | Timetables / RIS APIs | Rail realtime data. | Access and terms. |
| SNCF | Open transport APIs | Rail and transit data. | Realtime docs and license. |
| TomTom Traffic | Traffic APIs | Traffic flow and incident data. | Public access and license. |
| HERE Traffic | Traffic APIs | Traffic flow and incident data. | Terms and data rights. |
| Environment Canada | Weather alerts / feeds | Official weather public data. | API docs and update cadence. |
| Meteomatics | Weather API | Commercial weather observations/forecasts. | Realtime scope and terms. |
| WeatherKit | Weather API | Weather data feed. | Public-data terms and rate limits. |
| AccuWeather | Weather APIs | Weather observations and alerts. | License and redistribution. |
| Visual Crossing | Weather API | Weather observations/forecast data. | Realtime status and terms. |
| IRIS | Seismic feeds | Seismic waveform/event data. | API docs and near-realtime surfaces. |
| GDACS | Disaster alerts | Global disaster alert feeds. | Terms and CAP/API details. |
| Copernicus Atmosphere | Atmospheric data | Air quality and atmospheric monitoring. | Realtime/forecast feed docs. |
| ECMWF | Weather data feeds | Forecast and reanalysis data. | Open-data boundaries and live API status. |
| MET Norway | Weather API | Public weather forecasts. | Terms and rate limits. |
| UK Met Office DataPoint | Weather data feeds | Official UK weather data. | Current status and replacement APIs. |
| GovInfo | Government documents API | Official US government document updates. | Update cadence and terms. |
| data.gov | Catalog feeds | Public dataset update signals. | Realtime relevance and API docs. |
| Parliamentary APIs | Legislative feeds | Country-specific legislative activity. | Which jurisdictions expose live feeds. |
| Municipal open-data realtime feeds | City open-data APIs | Permits, incidents, transit, and civic data. | Official source per city. |
| NOAA CLASS | Satellite data access | Earth observation products. | Near-realtime availability. |
| Planet APIs | Satellite imagery/tasking APIs | Commercial earth-observation data. | Public-interest access and licensing. |
| Maxar | Earth intelligence feeds | Satellite imagery and analytics. | API docs and data rights. |
| Argo floats | Ocean observations | Public oceanographic sensor data. | Near-realtime feed docs. |
| NOAA ERDDAP servers | Environmental datasets | Sensor and gridded environmental data. | Which datasets are near-realtime. |
| IOOS | Ocean observing feeds | Marine environmental observations. | API docs and terms. |
| API-Sports | Sports APIs | Live scores and events. | Official docs and terms. |
| OddsJam | Odds API | Sportsbook odds aggregation. | Docs and commercial terms. |
| DraftKings odds | Official/candidate odds feed | Public betting-market signal. | Official API access and legal permission. |
| FanDuel odds | Official/candidate odds feed | Public betting-market signal. | Official API access and legal permission. |
| Racing Post | Racing data feeds | Horse racing prices/results. | Developer docs and terms. |
| Sportmonks | Sports APIs | Football and sports live data. | Realtime docs and license. |
| LiveScore APIs | Live-score feeds | Sports event state. | Official API and terms. |
| StockX | Marketplace pricing | Public resale price signal. | Official API status and terms. |
| GOAT / Flight Club | Sneaker marketplace pricing | Public resale signal. | Official API availability. |
| Keepa | Amazon price history API | Marketplace price tracking. | Realtime status and license. |
| CamelCamelCamel | Price feeds | Retail price signal. | API availability and terms. |
| Zillow / Redfin | Real-estate listings | Housing market public signal. | Official API status and reuse rights. |
| Craigslist | Public listing feeds | Local-market public data. | Current feed availability and terms. |
This is a map, not a finished census. The weak spots are specific enough to be useful:
- Regional transit is badly fragmented. GTFS Realtime is common, but city, agency, and country coverage varies widely.
- Courts and public-record systems are jurisdiction-bound. Many systems expose feeds or dockets, but official APIs and reuse rights differ by court, state, and country.
- Sports and odds are rights-heavy. Official feeds are often paid, sublicensed, or contract-bound even when the underlying event is public.
- Aviation and maritime coverage is sensor-biased. Receiver geography, contributor density, satellite access, and redistribution rights shape the data as much as the protocol.
- Threat-intelligence feeds blur public benefit and commercial licensing. Many sources are public to query but not public to bulk republish.
- Social APIs change access quickly. Public activity, developer approval, retention limits, and anti-surveillance policies should be rechecked often.
- Public commerce and pricing signals are under-defined. Some are public to view, but official APIs are rare and reuse rights are often hostile.
- Government emergency feeds vary by standard. CAP, RSS, agency JSON, and local alert brokers are not interchangeable.
- Rate limits are incomplete unless stream-specific. REST quotas, connection limits, message limits, and data entitlements are different constraints.
- Terms links are often too general. API terms, data licenses, market-data agreements, and acceptable-use policies may override general ToS pages.
- Candidate entries are intentionally unresolved. Promote only after official docs, terms, access, and realtime semantics are verified.