Get mempool firehose connection info

This endpoint does not stream data itself. It returns a PolyWsConnectInfo object — an already-signed wss:// URL plus a short-lived auth token — that you use to open the actual mempool firehose WebSocket. The token is included as the first frame you send on the new connection, and it expires at expires_at, so call this endpoint immediately before connecting and refresh whenever a connection drops or the token nears expiry.

The mempool firehose delivers Polygon pending transactions as they enter the node mempool, before they are mined into a block. A single connection sees a baseline throughput of roughly 32–37 tx/s. Use it for mempool monitoring, pre-confirmation transaction tracking, MEV/orderflow analysis, and front-running detection dashboards.

The firehose is the highest-tier Polygon product surface and requires the business tier. Callers on a lower tier receive 403 tier_insufficient. Once connected, the WebSocket enforces the same auth and rate-limit rules and signals violations through the documented close codes.

For the WebSocket protocol itself — frame format, subscription messages, and keep-alive — see the firehose channel reference at /ws/polygon-bor-firehose.

This endpoint takes no path, query, or body parameters. Authentication is the only required input.

Response fields

Only url and expires_at are guaranteed present; token and close_codes are included on success.

All error bodies use the shared envelope (error, message, request_id). See errors.md for the full schema and per-code fields.

JavaScript (fetch)

const res = await fetch(
  "https://api.triport.io/v1/polygon/firehose/mempool/connect-info",
  { headers: { Authorization: `Bearer ${process.env.TRIPORT_API_KEY}` } }
);
if (!res.ok) throw new Error(`connect-info failed: ${res.status}`);
const info = await res.json();


const ws = new WebSocket(info.url);
ws.onopen = () => ws.send(info.token); // token as the first frame
ws.onmessage = (ev) => {
  const pendingTx = JSON.parse(ev.data);
  console.log("pending tx:", pendingTx.hash);
};
ws.onclose = (ev) => {
  if (ev.code === info.close_codes.unauthorized) {
    // token expired — re-request connect-info and reconnect
  }
};

TypeScript SDK (@triport/sdk)

import { Triport } from "@triport/sdk";


const client = new Triport({ apiKey: process.env.TRIPORT_API_KEY! });


const info = await client.polygon.firehose.mempool.connectInfo();
const stream = await client.polygon.firehose.mempool.connect(info);


for await (const tx of stream) {
  console.log("pending tx:", tx.hash);
}

Python (triport-sdk)

import os
from triport import Triport


client = Triport(api_key=os.environ["TRIPORT_API_KEY"])


info = client.polygon.firehose.mempool.connect_info()
with client.polygon.firehose.mempool.connect(info) as stream:
    for tx in stream:
        print("pending tx:", tx["hash"])

• Stateless, short-lived credentials. url and token expire at expires_at. Always fetch fresh connect-info right before opening a socket; do not cache it across reconnects.
• Throughput. Expect ~32–37 tx/s on a single connection. Pending transactions are not yet mined and may never be — handle drops/replacements on the consumer side.
• No daily cap. Rate limiting is RPS-per-tier with a burst multiplier; there is no daily quota.
• Related: the logs firehose connect-info at /v1/polygon/firehose/logs/connect-info (pro tier), and the live WebSocket channel /ws/polygon-bor-firehose.