x402 Payments

Overview

x402 is Coinbase’s protocol for autonomous agent payments. Agents pay per API call using USDC stablecoins — no API keys needed.

How It Will Work

1. Agent calls API (no auth)
2. Server returns HTTP 402 + payment instructions
3. Agent signs USDC payment
4. Agent retries with payment token
5. Server executes tool

Planned Networks

Network	Currency	Status
Base	USDC	🔜 First to launch
Ethereum	USDC	🔜 Planned

Current Alternative

Use API keys today — they work with all catalog tools (see All tools; playground tools-data.json lists all catalog tools):

curl -X POST https://api.50c.ai/tools/genius \
  -H "Authorization: Bearer cv_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"problem": "What is 2+2?"}'

Get your key at 50c.ai/subscribe.

Want Early Access?

Join the waitlist for x402 beta access: