§09 · API

Streams

Live trades and launches over Server-Sent Events and WebSocket.

WebSocket

Connect to wss://api.justi.fun/v1/ws (add ?key=jf_live_... in browsers, or an Authorization header elsewhere). The server greets with welcome; then subscribe to channels.

Channel	Events
launches	launch.created
trades	every trade
trades:<mint>	trades of one coin
graduations	coin.graduated
burns	burn

const sub = justi.subscribe(["launches", `trades:${mint}`], (e) => {
  if (e.event === "trade") console.log(e.data.side, e.data.solLamports);
});
// reconnects and resubscribes on its own; sub.add(...), sub.remove(...), sub.close()

Messages

→ {"op":"subscribe","channels":["trades:<mint>","launches"],"id":1}
← {"type":"welcome","channels":["launches","trades","trades:<mint>","graduations","burns"],"heartbeatSec":20,"tier":"anon","maxSubscriptions":20,"ts":1793110000}
← {"type":"subscribed","channels":["trades:<mint>","launches"],"id":1}
← {"type":"event","channel":"trades:<mint>","event":"trade","id":"evt_7804","ts":1793110266,"data":{ ...same as the webhook... }}
← {"type":"heartbeat","ts":1793110280}
→ {"op":"unsubscribe","channels":["launches"]}   → {"op":"ping"}   ← {"type":"pong","ts":...}
← {"type":"error","code":"invalid_params","message":"Unknown channel: ..."}

Server-Sent Events

GET /v1/stream sends event: trade and event: launch, with a heartbeat comment every 15 s. Add ?mint= for one coin. Good for browsers with EventSource and for curl -N.

curl -N "https://api.justi.fun/v1/stream?mint=<mint>"

SSE data

event: trade
data: {"mint","ticker","image","side":"buy","sol":"<lamports>","tokens":"<raw>","wallet","signature","ts","priceSol","mcapSol"}

event: launch
data: {"mint","ticker","name","image","ts"}

Limits

	anon	free key	partner key
Open streams at once (SSE + WS)	5	20	200
Subscriptions per WS connection	20	50	500
New connections	10 burst, 20/min	20, 60/min	100, 300/min

Client messages: 4 KB each, 30 per 10 s (more closes with 1008). A client that does not answer pings for 40 s is dropped. More than 4 MB of unread output closes with 1013. A bad key is refused with HTTP 401 before the upgrade, too many connections with 429.

Reference

#Server-Sent Events: trades and launches

GET/v1/stream

Key optionalRate class streamopenStream

event: trade data {"mint","ticker","image","side","sol","tokens","wallet","signature","ts","priceSol","mcapSol","ix","createTx"}; event: launch data {"mint","ticker","name","image","ts"}. Heartbeat comment every 15s. Optional ?mint= filter. For more channels use the WebSocket at /v1/ws.

Parameters

Name	Type	About
mintquery	address

Response: text/event-stream

Errors400 invalid_params401 unauthorized429 rate_limited500 internal

curl "https://api.justi.fun/v1/stream" -o out

#WebSocket

#Server-Sent Events