Mercury402: Treasury/FRED financial data over x402

Mercury402

Deterministic Finance Data for Autonomous Agents

Mercury402 provides pay-per-call economic data APIs for AI agents and autonomous systems. No API keys, no accounts, no rate limits—just pay in USDC on Base via the x402 protocol and get instant access to Federal Reserve data, Treasury yields, and macro indicators with cryptographic provenance.

Live at: https://api.mercury402.com

Endpoints

78 priced routes in /.well-known/x402 / src/pricing.js (FRED aliases, forex, spreads, breakeven, macro, composites, AI) plus free discovery/health/docs.

Discovery

Every document below is generated from src/pricing.js (what is charged) and the route modules, so they list the same 78 paid endpoints at the same prices.

curl -s https://api.mercury402.com/llms.txt
curl -s https://api.mercury402.com/meta.json | jq '.count, .endpoints[0]'

Quick Start

# 1. Try a free health check
curl https://api.mercury402.com/health

# 2. Attempt to access data (returns 402 Payment Required)
curl https://api.mercury402.com/v1/fred/UNRATE

# 3. Pay via an x402-compatible client and retry with payment-signature
curl -H "payment-signature: <base64_x402_payment_payload>" \
  https://api.mercury402.com/v1/fred/UNRATE

See examples/ for agent integration code.

Use with MCP

The mercury402-mcp server exposes two tools, list_endpoints and get_endpoint_data, over the same 78 endpoints.

npx -y mercury402-mcp

Claude Code:

claude mcp add mercury402 -- npx -y mercury402-mcp

Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "mercury402": {
      "command": "npx",
      "args": ["-y", "mercury402-mcp"]
    }
  }
}

Hosted endpoint (free discovery mode: lists endpoints and returns 402 quotes, never pays): https://mcp.mercury402.com/mcp

Other MCP clients can run the same npx -y mercury402-mcp command over stdio. Paid mode and all configuration options: mcp-server/README.md.

x402 Payment Flow

1. Request data → Server returns 402 Payment Required with Payment-Required details
2. Pay in USDC → Use an x402-compatible client on Base to build a signed payment payload
3. Retry request → Include payment-signature: <base64_x402_payment_payload>
4. Receive data → Server verifies and redeems the payment, then returns signed data

Marketplace listing: https://www.x402scan.com/server/mercury402

Documentation

• Swagger UI: https://api.mercury402.com/docs/api
• OpenAPI Spec: https://api.mercury402.com/openapi.json
• x402scan Listing: https://www.x402scan.com/server/mercury402
• Examples: examples/README.md

Features

✅ No API keys or accounts — Pay-per-call via USDC on Base
✅ Deterministic data — All responses include FRED series metadata and provenance signatures
✅ Cryptographic provenance — ECDSA signatures verify data authenticity
✅ Rate-limited free tier — Health and discovery endpoints always available
✅ Agent-friendly — Designed for autonomous systems and AI agents

Tech Stack

• Runtime: Node.js + Express
• Data source: Federal Reserve Economic Data (FRED) API
• Payment: x402 protocol (USDC on Base)
• Signing: ethers.js + ECDSA

Self-Hosting

# Clone and install
git clone https://github.com/dudman1/mercury402.git
cd mercury402
npm install

# Configure environment
cp .env.example .env
# Add your FRED_API_KEY and SERVER_PRIVATE_KEY

# Start server
npm start

Server runs on http://localhost:4020

See deployment docs for production setup.

Support

Issues: GitHub Issues
Funding: https://api.mercury402.com

License

MIT

Last updated: 2026-10-08 ET | Updated by: Hermes