x402

P2P Protocol

Open HTTP-native payment protocol that activates the dormant HTTP 402 'Payment Required' status code to enable instant stablecoin micropayments between clients and servers — including AI agents — without accounts, API keys, or KYC. A client receiving a 402 response pays in stablecoins and retries; the server grants access upon verification by a facilitator. Chain-agnostic, zero-protocol-fee, designed as a foundational internet primitive for the agentic economy. 100M+ payments processed since May 2025 launch.

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Details

License Open source — Apache 2.0; GitHub: github.com/coinbase/x402
Dev Status 🟢 Active
Dev Status Detail Production — V2 specification released; 100M+ payments processed
Owner x402 Foundation (co-founded by Coinbase and Cloudflare, September 23, 2025); protocol created by Erik Reppel at Coinbase Developer Platform
Governing Body x402 Foundation (industry consortium co-founded by Coinbase and Cloudflare, September 2025)
Country USA
Start Year 2025
Stack TypeScript/JavaScript (primary SDKs: @x402/core, @x402/express, @x402/fetch, @x402/next); Go; Rust
Funding Coinbase Developer Platform (corporate originator); x402 Foundation (neutral governance)
Last Investigated Jan 15, 2026

Topology view

This tool in the centre and the things it is directly related to. Each line names the kind of relationship.

Topology view: x402This tool in the centre and the things it is directly related to. Each line names the kind of relationship.x402ERC-8004 (Aims to interoperate with)ERC-8004Ethereum (Based on)EthereumBitcoin (Inspired by)Bitcoin

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Use Case Domains

Mutual Aid & Exchange

Affordances

Non-monetary exchange Transparent stewardship

P2P Protocol Attributes

Origins Inspired by Balaji Srinivasan's 21.co Bitcoin micropayment channels (2015); HTTP 402 status code originally reserved in HTTP/1.1 but never standardized; x402 revives and formalizes it for the stablecoin and agentic era
Database N/A — stateless payment protocol
Query Language N/A
Data Formats JSON (payment payload); EIP-712 signed payment authorization header
Collaborative Live Editing No
Rich Text Editing No
Mobile Support Yes (mobile HTTP clients)
Web Support Yes (HTTP-native)
Native Apps Yes
Terms Apache 2.0
Funds N/A (corporate-originated open standard; foundation-governed)
Based On HTTP/1.1 RFC 7235 (402 status code); EIP-712 (Ethereum typed structured data signing); USDC/stablecoin payment rails
P2P Architecture Client-server (HTTP request-response with facilitator for payment verification and settlement)
Overlay Network N/A — HTTP transport
Content Addressing No
Local-First No
E2EE No (payment authorization in HTTP header; no E2EE channel established)
CRDTs Lib N/A
Byzantine Fault Tolerance N/A
Signature Yes — EIP-712 cryptographic signature on payment payload
Permissions Key-based (EIP-712 signed payment authorization; no account or API key required)
Semantic Web Compatibility No
Smart Contract No (payment protocol; blockchain settlement via EVM/SVM facilitator)
Protocol Stack Position Application-layer (built on HTTP/HTTPS)
Asset / Value Embedding Application-layer add-on — value transfer handled via external blockchain facilitator, not embedded in the network packet
Protocol Maturity / Standardization Production / Open Standard — V2 specification released; x402 Foundation (Coinbase + Cloudflare) governs; 100M+ payments processed; ERC-8004 integration on roadmap; not submitted to IETF

Relationships

How this tool connects to other tools and organizations, from relationships reviewed by the OpenHaven data steward. They describe how projects connect, not how good they are.

Aims to interoperate with
Based on
Inspired by