Kraken Crypto Signals — x402 pay-per-call API

Pay-per-call crypto market-state data for AI agents, served over the x402 protocol on Base mainnet. An agent calls an endpoint, receives HTTP 402, pays USDC, and gets machine-readable, ECDSA-signed data — no accounts, no API keys.

Live: https://signals.nsgoods.org · Manifest: https://signals.nsgoods.org/.well-known/x402 · OpenAPI: https://signals.nsgoods.org/openapi.json On x402scan: https://www.x402scan.com/server/bcc5723d-17eb-40f2-9e23-c1f2e3387dd2 · Demo (40s): https://youtu.be/k2WhYqK1YvQ

Why this API

• Signed & verifiable — every response carries signed_by + signature; recover against the published signer to prove it is authentic and untampered.
• Provable track-record — a public commit-reveal hash chain (/track-record) lets anyone audit past calls; /history reveals older snapshots with their hashes.
• Proof of edge — /backtest replays the live strategy over recent history and returns win-rate + average forward return, so an agent can measure the edge before subscribing.
• No keys, no signup, free preview — try /signals/preview for free, then pay per call in USDC on Base.

Quickstart (call & pay in ~5 minutes)

A runnable demo agent lives in examples/quickstart. It calls the FREE /signals/preview endpoint and then prints the decoded x402 402 Payment Required challenge for a paid endpoint — no funds needed. Add a low-balance Base hot-wallet key and the same call auto-pays in USDC on Base.

cd examples/quickstart
npm install
cp .env.example .env      # leave WALLET_PRIVATE_KEY empty for the no-funds demo
node agent.js

Paid endpoints: /indicators ($0.005), /signals ($0.01), /regime/changed ($0.02), /history ($0.05), /signals/top ($0.10), /backtest ($0.25) — USDC on Base mainnet (eip155:8453), payTo 0xc87a06DEE4c0E85912296002617120BBfd5EF990.

Build an agent on this API

Starter template (free preview → paid pay-per-call over x402): https://github.com/Nikoble1926/agent-starter-x402

Paid endpoints

Free endpoints

Any active Kraken */USD spot pair works via ?pair= (e.g. ETH/USD, SOL/USD, XRP/USD, DOGE/USD).

Verify a signed response

Every response carries signed_by + signature: an EIP-191 personal_sign over the JSON body (canonical json.dumps(sort_keys=True, separators=(",",":"))) before those two keys are added. Anyone can recover the signing address and confirm it equals the published signer 0x5e63d01d6A266BC17f577B80199a2a07B15053C7 — proving the signal is authentic and untampered, without paying. examples/verify_signature.py does exactly this against the FREE /signals/preview endpoint:

pip install eth_account
python examples/verify_signature.py    # -> VERIFIED ✓  recover == signed_by == signer

Discovery

Listed on [x402scan](https://www.x402scan.com/server/bcc5723d-17eb-40f2-9e23-c1f2e3387dd2) and the [x402 Bazaar](https://docs.cdp.coinbase.com/x402/bazaar) (CDP Facilitator) — agents can find this API via Bazaar semantic search / merchant lookup for payTo 0xc87a06DEE4c0E85912296002617120BBfd5EF990. Settlement runs through the Coinbase CDP Facilitator.

Use with Claude Desktop / Cursor (MCP)

The mcp/ bridge exposes every endpoint as a tool; paid tools settle USDC on Base automatically per call, and get_signal_preview is free. See mcp/ for setup.

Run

pip install -r requirements.txt
cp .env.example .env   # set your PUBLIC Base receiving address
python signals_api.py

Security

Only your public Base receiving address goes in .env. Never put a private key or seed phrase in this repo.

Disclaimer

Educational signals from a multi-timeframe strategy. Not financial advice. /backtest is a recent-window walk-forward replay, not a long-horizon study; past performance does not predict future results.