Agentic Payments

AI agents need to discover, pay for, and consume resources and services programmatically. Traditional onboarding requires account creation, a payment method, and an API key before an agent can pay for a service. Agentic payments let AI agents purchase resources and services directly through the HTTP 402 Payment Required response code.

Cloudflare's Agents SDK supports agentic payments through two protocols built on the HTTP 402 Payment Required status code: x402 and Machine Payments Protocol (MPP). Both follow the same core flow:

1. A client requests a resource or calls a tool.
2. The server returns a payment Challenge describing what to pay, how much, and where.
3. The client fulfills the payment and retries the request with a payment credential.
4. The server verifies the payment (optionally through a facilitator service) and returns the resource along with a receipt.

No pre-created service account or pre-shared API key is required. Agents handle the payment exchange programmatically.

x402 ↗ is a payment standard created by Coinbase. It uses on-chain stablecoin payments (USDC on Base, Ethereum, Solana, and other networks) and defines three HTTP headers — PAYMENT-REQUIRED, PAYMENT-SIGNATURE, and PAYMENT-RESPONSE — to carry challenges, credentials, and receipts. Servers can offload verification and settlement to a facilitator service so they do not need direct blockchain connectivity. It is governed by Coinbase and Cloudflare, two of the founding members of the x402 Foundation.

The Agents SDK provides first-class x402 integration:

• Server-side: withX402 and paidTool for Model Context Protocol (MCP) servers, plus x402-hono middleware for HTTP Workers.
• Client-side: withX402Client wraps MCP connections with automatic 402 handling and optional human approval.

Machine Payments Protocol (MPP) ↗ is an open payment protocol. It adds the WWW-Authenticate: Payment and Authorization: Payment headers to HTTP 402 responses.

MPP supports multiple payment methods beyond blockchains, including cards (via Stripe) and stablecoins. The mppx SDK supports one-time, usage-based, and recurring payments. MPP is also backwards-compatible with x402: MPP clients can consume existing x402 services without modification.

• x402.org ↗ — x402 protocol specification
• mpp.dev ↗ — MPP protocol specification
• Pay Per Crawl — Cloudflare-native monetization for web content
• x402 examples ↗ — Complete working code