X402 Api Paywall

Turn your API into a Revenue Stream

Modern AI agents need a way to pay for the services they consume. The x402 API Paywall skill enables you to monetize your Express or FastAPI endpoints using the HTTP 402 "Payment Required" standard and stablecoins.

What it does

This skill acts as a specialized developer assistant that integrates a middleware-based paywall into your existing codebase. Instead of manually writing complex web3 verification logic, the skill automatically implements the x402 handshake: it detects missing or invalid payment proofs, returns machine-readable 402 errors with payment requirements, and verifies proof-of-payment on the server side before granting access to your protected routes.

Supported Tools & Frameworks

• FastAPI (Python): Implements via route dependencies for granular control.
• Express (Node.js): Implements via standard middleware mounting.
• Stablecoin Ecosystem: Built for USDC and other assets on networks like Base.
• Verification: Integrates with facilitator services for secure, server-side proof validation.

Why use this over raw prompting?

Implementing a cryptographically secure paywall requires precise handling of headers, status codes, and external verification APIs. This skill understands the specific architecture of the x402 protocol, ensuring you don't leak "free" requests through logic errors or hardcode sensitive wallet information. It follows a non-destructive path, protecting only the routes you choose while keeping your existing business logic and public endpoints intact.

Built by Nex AI. More skills and info at nex-ai.be and slopsome.com.