x402 V1 → V2 Migration Guide


Field notes from migrating a live, payment-gated API from x402 V1 to V2 on Base mainnet — the undocumented gotchas, working code from a service in production, and a checklist at the bottom.

Written from x402ai, which settles real USDC on Base via the Coinbase CDP facilitator. Every code sample here is running in...