P402 Protocol

AI payment router. Route across 300+ models, settle per request in USDC on Base or USDC.e on Tempo.

P402 sits between your AI application and every LLM provider. It handles intelligent multi-provider routing (cost / quality / speed / balanced), on-chain micropayment settlement via the x402 protocol and mppx on Base and Tempo, and spending guardrails for autonomous agents.

Why P402

Quick Start (VS Code / Cursor / Windsurf)

Install the extension — the MCP server is embedded, tools appear in Copilot agent mode immediately, no config files required:

ext install p402-protocol.p402

Then run P402: Configure API Key from the command palette.

→ VS Code Marketplace · Open VSX

Quick Start (Claude Desktop / any MCP client)

{
  "mcpServers": {
    "p402": {
      "command": "npx",
      "args": ["-y", "@p402/mcp-server"],
      "env": { "P402_API_KEY": "p402_live_..." }
    }
  }
}

→ MCP docs · MCP Registry

Quick Start (SDK)

npm install @p402/sdk

import P402Client from '@p402/sdk';

const p402 = new P402Client({ apiKey: process.env.P402_API_KEY });

// Drop-in OpenAI replacement — P402 picks the best provider
const response = await p402.chat({
  messages: [{ role: 'user', content: 'Explain x402 payments in one sentence.' }],
  p402: { mode: 'cost' }   // cost | quality | speed | balanced
});

console.log(response.choices[0].message.content);
// p402_metadata: { provider: 'deepseek', cost_usd: 0.00031, latency_ms: 412 }

Quick Start (CLI)

# Authenticate once
npx p402 login

# Chat using the cheapest provider
npx p402 chat "What is x402?" --mode cost

# Check facilitator health
npx p402 health

Routing Modes

Session Budgets

Enforce hard spending caps for autonomous agents:

// Create a $10 session — agent cannot spend a cent more
const session = await p402.createSession({ budget_usd: 10 });

// All chat requests are deducted from the session
const response = await p402.chat({
  

... [View full README on GitHub](https://github.com/Z333Q/p402-protocol#readme)