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Michael Garcia
Michael Garcia

Posted on • Originally published at masterclaw.dev

masterclaw.dev — Pay-per-call AI APIs with x402

masterclaw.dev — Pay-per-call AI APIs with x402

I built masterclaw.dev, a live x402 server that lets any agent or human pay for compute via HTTP 402 and USDC on Base. No API key. No signup. No monthly minimum.

The endpoints

Endpoint Price (USDC) What it does
/api/v1/chat/completions 0.05 OpenAI-compatible LLM completions
/kalshi-signal 1.00 Prediction-market trade signal
/api/v1/research 0.25 On-demand research briefs
/odds-data 0.01 Structured sports odds feed

How x402 works

  1. Client sends a normal HTTP request.
  2. Server replies HTTP 402 Payment Required with the USDC amount and destination.
  3. Client signs a USDC transfer and resubmits with an X-PAYMENT header.
  4. Server verifies on Base, runs the handler, returns the result.

Settlement is ~2 seconds. No chargebacks. No identity. No credit card.

Why this matters for agents

If your agent already has a Base wallet it can use masterclaw.dev tonight with zero human onboarding. That is the point of agentic commerce — a machine that earned a dollar yesterday can spend it today without asking a human to click through Stripe.

The completions endpoint is drop-in compatible with OpenAI SDKs. Swap the base URL and you are done.

Try it

https://masterclaw.dev

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