x402 vs Agent Payments Protocol
The map lists them as complementary: sites and agents commonly implement both.
| x402 | Agent Payments Protocol AP2 | |
|---|---|---|
| Lifecycle step | 7 Pay: Settle the bill | 7 Pay: Settle the bill |
| Answers | How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup? | Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later? |
| Governed by | x402 Foundation, a Series of LF Projects, LLC (Linux Foundation); operational launch announced 2026-07-14; Executive Director Michael Hursta from 2026-10-01; 50+ members | Google; core specification donated to the FIDO Alliance (Payments TWG and Agentic Authentication TWG), 2026-04-28; the google-agentic-commerce/AP2 repository now hosts only samples and an SDK, not the normative spec text |
| Status (issuer's words) | Open, neutral standard for internet-native payments | Security/authorization protocol for agent-performed payments; core spec now stewarded by FIDO Alliance |
| Phase | living | candidate |
| Version | x402 protocol specification v2, transports-v2/http.md | v0.2.0 (2026-04-28) |
| Form / transport | HTTP header | endpoint |
| Found at | none — signalled per-request via the 402 status code, not a fixed well-known path | none |
| Adoption | claimed — x402 Foundation (x402.org live dashboard) | claimed — Google (launch blog post, 60+ launch partners) |
| Evidence | 5 verified | 4 verified, 2 reported |
| Primary use case | Accept payments from agents | Let agents buy on behalf of a person |
| Last verified | 2026-10-19 (current) | 2026-10-19 (current) |
| Specification | https://github.com/x402-foundation/x402/blob/main/specs/transports-v2/http.md | https://raw.githubusercontent.com/google-agentic-commerce/AP2/main/docs/ap2/specification.md |
When to use which
- Choose x402 when your question is “How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup?” and you accept its maturity: phase living, adoption claimed (x402 Foundation (x402.org live dashboard)).
- Choose Agent Payments Protocol when your question is “Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later?” and you accept its maturity: phase candidate, adoption claimed (Google (launch blog post, 60+ launch partners)).
Read the full articles
- x402: How can an HTTP client pay per-request or per-resource, in stablecoins, without accounts, API keys, or signup?
- Agent Payments Protocol: Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later?