25 tiny x402 payment endpoints on Base USDC, each demonstrating a different payment pattern.

x402 Toolbox is a set of 25 small, real endpoints on Base mainnet USDC, each demonstrating a distinct x402 payment pattern: escrow, invoicing, subscriptions, auctions, prediction markets, oracle attestations, and more. Every endpoint is a working example, not a mock — pay a few cents in USDC and get a real response. No API keys, no signup: an agent hits an endpoint, receives a 402 with payment terms, pays, and gets data back in one round trip. A free MCP server exposes 14 read-only tools covering the cheap, side-effect-free subset. A live demo shows a Claude agent playing both sides of a transaction — autonomously issuing an invoice, then autonomously paying it — with no human in the loop.