ShinyDapps/l402-kit

What it does

ShinyDapps/l402-kit is a comprehensive L402 (HTTP 402 Payment Required) SDK that enables developers to build payment-gated AI services and LLM agent integrations. It provides server-side middleware for popular frameworks (Express, FastAPI, axum, net/http) and a client-side agent with automatic payment capability, allowing seamless monetization of API endpoints and AI capabilities.

How to set up

Installation is straightforward via npm for the MCP server: npx l402kitmcp. Choose your language (TypeScript, Python, Go, or Rust) and integrate the appropriate middleware into your existing server. Configure budget limits and payment parameters, then integrate with LangChain if using agent-based workflows.

Key features

• Fullstack L402 protocol implementation across 4 programming languages
• Server middleware for Express, FastAPI, axum, and net/http frameworks
• Agent client with automatic payment authorization
• Budget control and payment limit enforcement
• MCP server integration for AI model interaction
• LangChain compatibility for agent workflows
• Cross-platform support (macOS, Windows, Linux)