Backend
Backend integrations protect resources and coordinate settlement. Use backend middleware when you are the seller, and direct SDK operations when you need wallet, collateral, or operator-facing actions.TypeScript
Use@4mica/x402 for Express middleware and server-side 4Mica x402 support. It wires protected routes, guarantee verification, facilitator calls, and scheme registration.
Python
Use4mica-x402 for FastAPI or Flask middleware. Use sdk-4mica for collateral management, balances, and on-chain operations.
Rust
Usesdk-4mica for collateral and wallet operations. HTTP server middleware is planned, so use TypeScript or Python when you need production x402 middleware today.