Protocol Wars: x402 vs ACP vs UCP - Which Should Your Agent Use?

Three competing standards now exist for how AI agents pay for things. If you're building agents that need to transact - buy API calls, pay for compute, settle invoices - you have to pick one. Or do you? x402, ACP, and UCP each approach agent payments differently. Here's what actually matters about each, where they overlap, and how to avoid getting locked into a protocol that might lose. x402: HTTP-Native Payments from Coinbase x402 takes the simplest approach: bolt payments directly onto