x402 vs AP2
The most common confusion in agentic payments. x402 is a settlement rail; AP2 is an authorization layer. They're not really competitors — they compose.
The short answer
AP2 proves an agent is allowed to spend (mandates + verifiable credentials). x402 actually moves the money (USDC over HTTP 402). Because AP2 is payment-method-agnostic, x402 can be the rail an AP2 transaction settles over. It's "rail vs. permission," not "either/or."
Side-by-side
How they fit together
1. Authorize (AP2)
A mandate proves the user permitted this agent to buy, within limits.
2. Settle (x402)
The agent pays USDC over HTTP 402; a facilitator settles it on-chain.
3. Build today
x402 is shippable now; explore the ecosystem map and examples.
Frequently asked questions
Is x402 a competitor to AP2?
Not really — they operate at different layers and are often complementary. AP2 (Agent Payments Protocol) is an authorization framework: it uses signed “mandates” and verifiable credentials to prove an agent has permission to make a purchase on a user’s behalf. x402 is a settlement rail: it moves USDC over HTTP. AP2 is payment-method-agnostic and explicitly supports crypto rails like x402, so an AP2 transaction can settle via x402.
What is the difference between x402 and AP2?
x402 answers “how does the money move?” (HTTP 402 + a signed USDC transfer on-chain). AP2 answers “is this agent authorized to spend, and under what limits?” (mandates and verifiable credentials). One is the rail, the other is the permission/intent layer that can ride on top of it.
Can x402 and AP2 work together?
Yes. AP2 establishes that an agent is authorized to pay (the mandate), and x402 can be the rail that actually settles the USDC. They are designed to compose rather than replace each other.
Who is behind each protocol?
x402 was published by Coinbase as an open standard. AP2 was announced by Google with 60+ partners (including payment networks and crypto firms) as an open protocol for agent-led payments.
Which should I build on?
If you need to accept machine payments today on a pay-per-call API, x402 is the concrete, shippable rail. If your product is about agents making authorized purchases across many payment methods on a user’s behalf, AP2 is the authorization framework to track — and you may end up using both.
See also: What is AP2 · x402 vs Stripe · x402 vs L402 · full comparison