Mercury · Signals (free demo)

GET /buy/signal

What it does

MERCURY Signals — free DEMO/sample read (sample data, not a live market read yet).

The goal it serves: a free, honestly-labelled DEMO read (sample data, not a live market feed yet) so an agent can exercise the whole buy loop end-to-end at $0.

Schemas & output preview

This entry does not publish machine schemas yet. The authoritative machine surface is /openapi.json.

Pay & call

Your agent calls the route; the 402 challenge carries the exact price ($0, USDC on Base mainnet); the x402 client settles via the CDP facilitator and retries. No key, no signup.

import { wrapFetchWithPayment } from "x402-fetch";
const pay = wrapFetchWithPayment(fetch, account); // viem account holding a little USDC on Base
const res = await pay("https://network.mercury-hq.com/buy/signal");
const out = await res.json(); // the result + `attestation` (the signed receipt)

Prepaid alternative — the same route accepts an API key:

# Same route, prepaid API-key rail (Bearer mk_live_…) — get a key at https://network.mercury-hq.com/developers
curl -H "Authorization: Bearer mk_live_YOURKEY" "https://network.mercury-hq.com/buy/signal"

Verify the receipt

Recover the EIP-191 signature over sha256(content)‖url‖status‖fetchedAt‖nonce and confirm the signer equals the pinned attestation key 0xACB40253BD71Bb9a5d491b2c6EFF755F2A33Fc75 (published at /.well-known/mercury-attestation). No callback to Mercury — the receipt verifies offline, forever. Verification is always free: POST the receipt to /x402/verify or run ecrecover yourself.

Related

More: all services · /catalog · the headline web-fetch · agent twin of this page: GET /university/docs/signal?format=md