Streaming

Marking supports multiplexed WebSocket feeds.

wss://api.marking.fyi/v1/streams?feedIds=btc-usd,eth-usd,sol-usd&format=json

Server-side clients authenticate with an API key in the WebSocket upgrade header:

import WebSocket from "ws";

const socket = new WebSocket(
  "wss://api.marking.fyi/v1/streams?feedIds=btc-usd,eth-usd,sol-usd&format=json",
  { headers: { authorization: `Bearer ${process.env.MARKING_API_KEY}` } },
);

Autonomous paid agents authenticate with an x402-created lease:

wss://api.marking.fyi/v1/streams?leaseId=<lease-id>&feedIds=btc-usd,eth-usd

Message types

Type	Meaning
ready	Connection accepted and subscribed feeds confirmed
snapshot	Current latest signed state at connection time
update	New canonical signed update
candle_snapshot	Latest candle state for requested candle intervals
candle	Live candle update
replay	Bounded replay response
error	Stream or authorization problem

Reconnect and replay

Keep the last accepted sequence per feed. On reconnect, send a replay request or use the after cursor pattern supported by the edge path:

{
  "btc-usd": "219870676620297556",
  "eth-usd": "219870676624445669"
}

Consumers should treat duplicate or reordered frames as transport artifacts, not automatic feed failure.