Solana Chat

Decentralised chat where your Solana wallet is your identity. No phone numbers, no email signups, no single server controlling the network.

Why

Telegram is the default for crypto communities, but it requires a phone number, runs on centralised servers, and has no native concept of wallet identity. Solana Chat replaces that:

Your wallet is your identity — connect your Solana wallet, and that's your account. No passwords, no phone numbers, no KYC.
Your homeserver is your choice — a global onchain registry maps wallets to homeservers. You pick where your messages are stored. Switch anytime by signing a new delegation.
Federation, not centralisation — built on the Matrix protocol. Messages flow between homeservers. No single point of failure, no single company to trust.
Portable identity — your wallet address works across every homeserver. Move servers without losing your identity or breaking contacts.

How It Works

Connect wallet — Phantom, Solflare, Backpack, or any Wallet Standard compatible wallet
Pick a homeserver — choose a default or enter a custom homeserver URL
Register onchain — one transaction delegates your wallet to your chosen homeserver via the onchain registry (costs a fraction of a cent in rent)
Sign in — wallet signs a nonce challenge, homeserver verifies the ed25519 signature, auto-creates your account, and issues a Matrix session token
Chat — DMs by wallet address, group chats, rooms. Standard Matrix protocol under the hood.

After the initial wallet signature, everything uses Matrix session tokens. No wallet prompts while chatting.

Architecture

┌──────────┐     ┌───────────────────┐     ┌──────────────┐
│  Client   │────▶│  Matrix Homeserver │◀───▶│  Other       │
│  (React)  │     │  (Conduit + Solana │     │  Homeservers │
│           │     │   auth plugin)     │     │  (federated) │
└──────┬───┘     └───────────────────┘     └──────────────┘
       │
       │  register/lookup
       ▼
┌──────────────────┐
│  Solana Blockchain│
│  (Homeserver      │
│   Registry)       │
└──────────────────┘

Homeserver Registry (`programs/homeserver-registry/`)

An Anchor program that maps Solana wallet addresses to homeserver URLs. Each wallet gets a PDA (Program Derived Address) storing its delegation. Anyone can look up where to reach a wallet with a single RPC call.

Two instructions:

register(homeserver) — create or update your homeserver delegation. The homeserver must be a valid hostname (contains a dot, no protocol prefix, no spaces, max 253 characters).
unregister() — remove your delegation and reclaim rent. Only the owner can close their account.

The PDA is derived from the wallet address: ["delegation", owner_pubkey]. This means lookups don't require an index — derive the address, fetch the account.

import { getPDAAndBump } from "solana-kite";

const { pda } = await getPDAAndBump(PROGRAM_ID, ["delegation", walletAddress]);
const delegation = await connection.rpc.getAccountInfo(pda).send();

Server (`server/`)

Fork of Conduit, a fast Matrix homeserver written in Rust. Adds Solana wallet authentication via a custom login type.

Auth flow:

Client requests a nonce challenge:

POST /_matrix/client/unstable/org.solana.auth/nonce
{ "address": "7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU" }

Returns:

{
  "nonce": "a1b2c3...",
  "message": "Sign in to chat.example.com\n\nNonce: a1b2c3...\n\nThis signature will not trigger a blockchain transaction or cost any fees.",
  "expires_in_seconds": 300
}

Client signs the message field with the wallet (off-chain, no transaction).

Client sends the signature to the standard Matrix login endpoint:

POST /_matrix/client/v3/login
{
  "type": "m.login.solana.signature",
  "address": "7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU",
  "signature": "base58-encoded-signature",
  "nonce": "a1b2c3..."
}

Returns a standard Matrix login response with access_token, user_id, and device_id.

Nonce security:

Nonces expire after 5 minutes
Each nonce can only be used once (consumed on use)
In-memory store with automatic pruning at 10,000 entries
Server returns 404 if allow_solana_auth is disabled in config

Config options (in Conduit config):

allow_solana_auth — enable/disable Solana wallet authentication (default: false)
solana_auto_join_room — reserved for future auto-join on registration

Client (`client/`)

Vite + React web app with plain CSS. No Tailwind, no utility classes — semantic HTML with proper class names, flex/grid layout.

Stack:

@solana/react — wallet connection via Wallet Standard (works with Phantom, Solflare, Backpack, etc.)
@solana/kit — Solana transaction building and address handling
solana-kite — PDA derivation (getPDAAndBump), transaction sending (sendTransactionFromInstructionsWithWalletApp), message signing (signMessageFromWalletApp)
matrix-js-sdk — Matrix client for sync, rooms, messages, real-time updates

Features:

Connect any Wallet Standard compatible wallet
Pick a homeserver (default or custom URL)
Register homeserver delegation onchain
Sign in with wallet signature (off-chain, no transaction fees)
Find users by wallet address and start DMs
Create group chats with wallet addresses
Real-time messaging via Matrix sync
Dark theme, mobile responsive

Identity Scheme

Matrix localparts must be lowercase. Base58 has uppercase letters, and lowercasing creates collisions (e.g. 1 and l are different in base58 but both lowercase). Instead, the raw 32-byte public key is hex-encoded with a solana_ prefix:

solana_ prefix identifies the chain and distinguishes wallet accounts from regular Matrix accounts
64 hex characters after the prefix — always lowercase, always lossless
Extensible to other chains (ethereum_, cosmos_, etc.)
Total localpart length: 71 characters (well under Matrix's limit)

The base58 address is stored as the Matrix display name so users see the familiar Solana format.

Layer	Value
Matrix user ID	`@solana_a1b2c3d4e5f6...64hex:server`
Display name	`7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU`
Onchain PDA seeds	`["delegation", raw_pubkey_bytes]`

Running a Proof of Concept

This walks through getting all three components running locally so you can connect a wallet and chat.

Prerequisites

Node.js 22+
Rust (stable)
Solana CLI 3.1.8+ (sh -c "$(curl -sSfL https://release.anza.xyz/stable/install)")
Anchor CLI 0.32.1+ (cargo install --git https://github.com/coral-xyz/anchor anchor-cli)
A Solana wallet browser extension (Phantom, Solflare, or Backpack)

1. Deploy the Homeserver Registry to Devnet

# Configure Solana CLI for devnet
solana config set --url https://api.devnet.solana.com

# Fund your deployer wallet (needs ~2 SOL for program deployment)
solana airdrop 2

# Build and deploy the program
anchor build
anchor deploy --provider.cluster devnet

# Note the program ID from the output — update client/src/program.ts if different
# Current program ID: 27JU28YBf5RJmEHAn9BwnWFyfPMLkUdSafKgz9xQB9zn

Verify it deployed:

solana program show 27JU28YBf5RJmEHAn9BwnWFyfPMLkUdSafKgz9xQB9zn --url devnet

2. Run the Homeserver (Conduit)

The server needs ≥4GB RAM to compile in debug mode, or use --release with CARGO_BUILD_JOBS=1 on smaller machines.

cd server

# Build (release mode recommended — faster runtime, smaller binary)
cargo build --release --features conduit_bin,backend_sqlite

# Create a config file
mkdir -p /tmp/conduit
cat > /tmp/conduit/conduit.toml << 'EOF'
[global]
server_name = "localhost"
database_path = "/tmp/conduit/db"
database_backend = "sqlite"
port = 6167
max_request_size = 20_000_000
allow_registration = false
allow_federation = false
allow_check_for_updates = false
trusted_servers = ["matrix.org"]

# Enable Solana wallet authentication
allow_solana_auth = true
EOF

# Run the server
./target/release/conduit

The server will start on http://localhost:6167. Verify it's running:

curl http://localhost:6167/_matrix/client/versions

The nonce endpoint should also be available:

curl -X POST http://localhost:6167/_matrix/client/unstable/org.solana.auth/nonce \
  -H "Content-Type: application/json" \
  -d '{"address":"7xKXtg2CW87d97TXJSDpbD5jBkheTqA83TZRuJosgAsU"}'

3. Run the Client

cd client
npm install

# Point at your local homeserver (edit src/components/PickHomeserver.tsx
# DEFAULT_HOMESERVERS to include http://localhost:6167, or just type it
# in the custom homeserver field when the UI loads)
npm run dev

Open http://localhost:5173 in a browser with a Solana wallet extension installed.

4. End-to-End Flow

Click Connect Wallet — approve the connection in your wallet
The client checks for an existing onchain delegation. If none found, pick a homeserver.
Enter http://localhost:6167 as the homeserver URL
Approve the transaction — this registers your wallet→homeserver delegation onchain (costs a fraction of a cent on devnet)
Sign the challenge — the client requests a nonce, shows a message to sign (off-chain, no fees)
You're in. The Matrix client syncs and you can create rooms, DM by wallet address, etc.

Run All Tests

# Anchor program (10 tests)
anchor test

# Client (18 tests)
cd client && npm test

# Server auth (13 tests) — standalone crate, no Conduit build required
cd server/tests-rs && cargo test

Testing

Component	Tests	Coverage
Anchor program	10	Registration, updates, validation (empty/invalid/protocol prefix), access control, unregistration, re-registration, port numbers, PDA lookup
Client	18	Base58 encode/decode/roundtrip, hex encode/decode, base58↔hex localpart conversion, collision resistance, borsh string encode/decode, Matrix user ID format
Server	13	Nonce generation, hex localpart validity, hex↔base58 roundtrip, ed25519 sign/verify, wrong key rejection, tampered message rejection, nonce replay rejection, base58 signature roundtrip, invalid address rejection, wrong-length pubkey rejection, collision resistance, full auth flow simulation

Run all tests:

# Anchor program
anchor test

# Client
cd client && npm test

# Server
cd server && cargo test

Roadmap

Deploy registry to devnet
End-to-end test: wallet → onchain delegation → Conduit login → chat
.sol and .bonk name resolution for display names
Public room directory
Mobile app (after web client is proven)
Voice/video calls
Moderation tools for group chats
Sealed sender for metadata privacy

License

MIT

Name		Name	Last commit message	Last commit date
Latest commit History 28 Commits
.github/workflows		.github/workflows
client		client
programs/homeserver-registry		programs/homeserver-registry
server		server
tests		tests
.gitignore		.gitignore
Anchor.toml		Anchor.toml
Cargo.lock		Cargo.lock
Cargo.toml		Cargo.toml
LICENSE		LICENSE
README.md		README.md
package-lock.json		package-lock.json
package.json		package.json
rust-toolchain.toml		rust-toolchain.toml

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Solana Chat

Why

How It Works

Architecture

Homeserver Registry (`programs/homeserver-registry/`)

Server (`server/`)

Client (`client/`)

Identity Scheme

Running a Proof of Concept

Prerequisites

1. Deploy the Homeserver Registry to Devnet

2. Run the Homeserver (Conduit)

3. Run the Client

4. End-to-End Flow

Run All Tests

Testing

Roadmap

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Solana Chat

Why

How It Works

Architecture

Homeserver Registry (programs/homeserver-registry/)

Server (server/)

Client (client/)

Identity Scheme

Running a Proof of Concept

Prerequisites

1. Deploy the Homeserver Registry to Devnet

2. Run the Homeserver (Conduit)

3. Run the Client

4. End-to-End Flow

Run All Tests

Testing

Roadmap

License

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Homeserver Registry (`programs/homeserver-registry/`)

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