Broadcast API

https://broadcast.intentscan.net

The base URL returns a JSON descriptor for OIB/1 and the service route set. The six integration routes are:

{"protocol":"OIB/1","service":"intentscan-stream","routes":{"publish":"POST /v1/stream/publish","cursor":"GET /v1/stream/intents?since=<seq>","open_book":"GET /v1/stream/open","websocket":"GET /v1/stream/ws","sse":"GET /v1/stream/sse","health":"GET /v1/health"}}

WebSocket, SSE, cursor, and open-book intent events use the same envelope. Values below are abbreviated for readability. fill is the bearer authorization and settlement payload; the relay cannot forge it. summary is advisory display and filter data only, and must never reach pricing or execution.

{
  "event": "intent_open",
  "seq": 918273,
  "stream_epoch": "01J8Z6R3M4...",
  "data": {
    "id": "8453:agentswap:0xab10...",
    "origin": "native",
    "platform": "agentswap",
    "chain_id": 8453,
    "order_hash": "0xab10...",
    "fillable": "permissionless",
    "exclusive_until_ms": null,
    "fill": {"standard": "agentswap-v5.1", "settler": "0xC0b66...", "order": "0x...", "signature": "0x...", "resolver": null},
    "summary": {
      "input": {"token": "0x833589...", "amount": "1000000", "decimals": null, "symbol": null},
      "output": {"token": "0x420000...", "min_amount": "900000000000000", "decimals": null, "symbol": null},
      "created_ms": 1756800000000, "decay_end_ms": 1756800030000, "deadline_ms": 1756800300000
    },
    "observed_ms": 1756800000123,
    "source": "push:native"
  }
}

Native publishing currently fills summary.input.decimals, summary.input.symbol, summary.output.decimals, and summary.output.symbol as null.

Send a JSON object with exactly these request fields. order is ABI-encoded IntentOrder; its fields are owner, recipient, tokenIn, amountIn, tokenOut, startAmountOut, endAmountOut, startTime, decayEndTime, endTime, appData, and nonce. auth is the authorization bytes. chainId is optional.

{"order":"0x...","auth":"0x...","chainId":8453}

Production serves chain IDs 8453, 42161, 56, and 4663. When chainId is omitted, admission starts with 8453, the default, then searches the remaining served chains in order. Admission includes an eth_call to UserProxyV5.isIntentAuthorized.

Responses

curl -X POST https://broadcast.intentscan.net/v1/stream/publish \
  -H 'content-type: application/json' \
  --data '{"order":"0x...","auth":"0x...","chainId":8453}'

GET /v1/stream/open returns the current open intents and the sequence at which the snapshot was read.

{"seq":918273,"events":[]}

Each item in events is an intent envelope. On a cold start, read this book first, then subscribe with its seq as since.

GET /v1/stream/intents?since=<seq> returns events after the required numeric cursor.

{
  "stream_epoch": "01J8Z6R3M4...",
  "current_seq": 918280,
  "gap": null,
  "events": []
}

gap is either null or an object with last_seq. Use the returned stream_epoch with your stored cursor. A cursor gap means the requested history is not fully available.

Connect to wss://broadcast.intentscan.net/v1/stream/ws and send a text JSON subscribe frame first. since is optional and replays available history before live frames.

{"op":"subscribe","filters":{"chain_ids":[8453],"fillable":["permissionless"]},"since":918273}

Filters

Frame kinds

Every frame has event, seq, stream_epoch, and data.

const BASE = "https://broadcast.intentscan.net";
const socket = new WebSocket("wss://broadcast.intentscan.net/v1/stream/ws");
socket.addEventListener("open", () => socket.send(JSON.stringify({
  op: "subscribe",
  filters: { chain_ids: [8453], fillable: ["permissionless"] },
  since: 918273,
})));
socket.addEventListener("message", ({ data }) => {
  const frame = JSON.parse(data);
  console.log(frame.event, frame.data);
  if (frame.event !== "gap") return;
  fetch(`${BASE}/v1/stream/intents?since=${frame.data.last_seq}`)
    .then((response) => response.json())
    .then(console.log);
});

Connect to GET /v1/stream/sse. Every parameter is optional. since replays available history first. The filters are the WebSocket filters as query parameters, with list values comma-separated: chain_ids, platforms, fillable, tokens, and min_size_usd. A list item that does not parse, such as a non-numeric chain id or an unknown fillable value, answers 400 with a message naming the field. Each SSE data field carries the same JSON frame shape used by WebSocket.

const events = new EventSource(
  "https://broadcast.intentscan.net/v1/stream/sse?since=918273&chain_ids=8453,42161&fillable=permissionless"
);
events.onmessage = ({ data }) => {
  const frame = JSON.parse(data);
  console.log(frame.event, frame.data);
};

• Cold start: read /v1/stream/open, then subscribe with its seq in since.
• Gap: keep the connection open and backfill with /v1/stream/intents?since=<last_seq>. A gap is not a reconnect signal.
• Epoch: a changed stream_epoch means a full re-sync.
• Heartbeat: expect one every 20 seconds and reconnect after 3 missed heartbeats.
• Dual path: also run your own eth_getLogs floor or upstream poll, and deduplicate on id. This stream is an optimization, never the source of truth.
• Pricing: treat summary as advisory. Decode and verify fill before pricing or execution.

The edge allows CORS from any origin, the Content-Type header, and GET, POST, and OPTIONS. Preflight max age is 600 seconds. Health and read timeouts are 10 and 30 seconds, publish read timeout is 15 seconds, and stream read/send timeouts are 3600 seconds.

GET /v1/health returns 200 when the store is readable and the on-chain source is running. Otherwise it returns 503 with status: "degraded".

{"status":"ok","store_readable":true,"last_onchain_poll_completed_ms":1756800000123,"onchain_source_status":"running"}

last_onchain_poll_completed_ms is null before the first completed poll. onchain_source_status is running, stopped, or not_polled.