XRT Total Supply API

A small Express service with a single endpoint that returns the combined total supply of the XRT token of the Robonomics parachain.

Two non-overlapping parts are summed:

Source	What we count	Query
Robonomics parachain (Polkadot, paraId 3388)	native token issuance	balances.totalIssuance
Polkadot Asset Hub (paraId 1000)	XRT teleported to Asset Hub	foreignAssets.asset(<XRT XCM location>) → supply

total = totalIssuance(Robonomics) + supply(XRT on Asset Hub)

Why there is no double counting

XRT moves to Asset Hub via the teleport model: tokens are burned on Robonomics and re-issued on Asset Hub. Verified: the Asset Hub sovereign account on Robonomics holds 0 XRT, i.e. there is no reserve there, and the Robonomics totalIssuance no longer includes those tokens. Hence the two parts are independent.

The XRT wrapper bridged into Asset Hub from Ethereum (Snowbridge) is a different token origin and is intentionally not included in the total.

Running

Local

npm install
npm start          # http://localhost:3000
# or with auto-restart on changes:
npm run dev

Docker

cp .env.example .env   # adjust variables if needed
docker compose up --build

The app will be available at http://127.0.0.1:${APP_PORT} (default 3000). The port is bound to 127.0.0.1 only — it is not reachable from outside the host.

To use a different port:

APP_PORT=8080 docker compose up          # different host port, container still on 3000
APP_PORT=8080 PORT=8080 docker compose up  # both host and container port

Endpoint

GET /

Returns only the total supply value as plain text, already formatted with decimals (whole XRT). Query param ?force=true — bypass the cache.

5119335.029711074

GET /full

Query param ?force=true — bypass the cache and hit the network directly.

Example response:

{
  "token": "XRT",
  "decimals": 9,
  "totalSupply": "5119335029711074",
  "breakdown": {
    "robonomics": "4713289129711074",
    "assetHub": "406045900000000"
  },
  "updatedAt": "2026-06-05T10:27:49.689Z",
  "cached": false
}

All amounts are returned in planck (the smallest unit) as strings. Use decimals (9) to convert to whole XRT — e.g. 5119335029711074 / 10^9 = 5119335.029711074 XRT.

GET /health

Liveness probe: { "status": "ok" }.

Configuration (environment variables)

Variable	Default	Purpose
APP_PORT	3000	Host port mapped by Docker — bound to 127.0.0.1 (Docker only)
PORT	3000	HTTP server port (inside the container or local)
HOST	0.0.0.0	Bind address
ROBONOMICS_WS	wss://polkadot.rpc.robonomics.network/	Robonomics RPC
ASSET_HUB_WS	wss://polkadot-asset-hub-rpc.polkadot.io	Asset Hub RPC
CACHE_TTL_MS	10000	Response cache TTL (ms)

Copy .env.example to .env and edit as needed. All variables are optional — defaults work out of the box.

Structure

index.js          — entry point
src/config.js     — configuration
src/polkadot.js   — parachain connections and queries
src/supply.js     — total supply calculation + cache
src/format.js     — planck summation helper (BigInt)
src/server.js     — Express app and endpoints