Larkin
Provides Ed25519-signed trust scores for wallets paying via x402, enabling APIs to block, warn, or surcharge based on trust thresholds.
Larkin is an authorization layer for APIs that accept x402 payments, providing Ed25519-signed trust scores for paying wallets. It solves the problem of not knowing who is paying by scoring wallets across five dimensions and returning a signed receipt in under 200ms. The product targets developers and IT teams at businesses of all sizes, from startups to enterprises, who need to control access to their APIs. It is positioned as a complement to x402 payment infrastructure, offering three modes (block, warn, surcharge) and an open-core model with an MIT-licensed SDK and verifier.
Key features
- Ed25519-signed trust scores
- Three modes: block, warn, surcharge
- Scores across 5 dimensions
- Response in under 200ms
- Open-source verifier and CLI
- MCP server with check_wallet tool
- SDK for Next, Hono, Express
- Free tier: 10,000 checks/month
- No social media activity within the last 30 days
GTM channels
- API
- Docs
ICP
- Software developers
- Engineering teams
- IT teams