There’s a catalog at x402engine.app tracking every API that accepts x402 payments. It’s at 45 and counting.
Most people still treat x402 as a protocol spec. It’s past that. Data APIs, compute endpoints, content services. All accessible via a payment challenge over HTTP. No API key registration. No OAuth. No subscription management. You hit the endpoint, pay, get the response.
What makes the catalog interesting isn’t the number. It’s who can use it. Any client that can sign a payment authorization can access all of this autonomously. That includes AI agents.
Most agent tooling asks: what can the agent do? x402 asks: what can the agent buy? An agent with a wallet can work through this catalog and settle in USDC on-chain, without asking anyone.
I used x402 to mint a token last week. That was one endpoint. The catalog has 44 more.
The catalog is early. Most entries are small. But the shape of it is there.