| Name | Description | Languages | Links |
|---|---|---|---|
| World AgentKit | Verify human-backed agents | TypeScript | GitHub · npm |
| OMATrust | Key authorizations for Signed Offers and Receipts | TypeScript | GitHub · npm |
| PEAC Protocol | Verifiable receipts for x402 payments | TypeScript | GitHub · npm |
| x402r | Non-custodial refund and arbitration protocol | Typescript | GitHub · npm |
| zauth | Monitoring, verification, and refund SDK | TypeScript | GitHub · npm |
| x402aff | Affiliate builder-code revenue splits | Python, TypeScript | GitHub · PyPI · npm |
Developer Tools
Third-Party Extensions
Packages built by ecosystem partners that extend x402 beyond the core specification.