Learn / x402 vs AP2: what's the difference?
x402 vs AP2: what's the difference?
Short answer: x402 moves the money; AP2 proves the agent was allowed to move it. They are not competing rails so much as adjacent layers — execution vs authorization — and production agent stacks increasingly use ideas from both.
x402 in one paragraph
x402 (Coinbase → Linux Foundation, 40-member governance) revives HTTP 402 so any server can demand a stablecoin micropayment per request. It's live at scale: ~75M payments/~$24M in a recent 30-day window, settling in USDC on Base/Solana in under two seconds.
AP2 in one paragraph
AP2 (Google) defines verifiable mandates — signed proofs that an agent may spend under specific limits on its principal's behalf. It's rail-agnostic: a mandate can authorize card, bank, or stablecoin settlement. It's earlier-stage, with authorization rather than settlement volume as its value.
How to choose
Metering an API or selling data to agents → implement x402. Building an agent that spends real budgets, or a merchant that needs proof-of-authority → watch AP2 and demand mandates. Most serious stacks will end up with x402 execution wrapped in AP2-style authorization.
Frequently asked questions
Can x402 and AP2 be used together?
Yes — that's the expected end-state: AP2 mandates authorize the spend, x402 executes and settles it.
Which has more adoption?
x402 by a wide margin as of mid-2026 (millions of daily payments, Linux Foundation governance, 40 members). AP2 is an emerging spec whose adoption is measured in wallet/merchant integrations.
Does Google oppose x402?
No — Google is a premier member of the x402 Foundation while also driving AP2, consistent with the layers being complementary.
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