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Agentic Payments, HTTP 402 & Commerce

HTTP 402 Payment Required challenges, Coinbase x402 on-chain micro-settlement, and Machine Payments Protocol (MPP).

Executive Overview

As autonomous agents query paid APIs, execute complex compute tasks, and transact across services, agentic commerce protocols provide cryptographic micro-settlements without human credit card friction.

1. The HTTP 402 Execution Cycle

The native web payment handshake follows a deterministic 4-step sequence:

  1. Discovery Request: The agent requests a protected API resource or paid MCP tool.
  2. HTTP 402 Challenge: The server returns 402 Payment Required with headers defining the required asset, price (e.g. 0.001 USDC), and supported payment rails (x402 or MPP).
  3. Autonomous Signing: The agent's embedded wallet or authorized payment client signs the transaction payload.
  4. Settlement & Delivery: The agent retries the request with Authorization: x402 <signature>. The server verifies on-chain settlement and immediately delivers the resource payload with a receipt header.

Frequently Asked Questions

Why is HTTP 402 better for AI agents than traditional Stripe subscriptions?

Subscriptions require human account creation, credit card entry, and recurring monthly commitments. HTTP 402 enables instant, sub-cent pay-per-call micro-settlements without manual human registration.

AI Summary

As autonomous agents query paid APIs, execute complex compute tasks, and transact across services, agentic commerce protocols provide cryptographic micro-settlements without human credit card friction.