Agent Payment Protocols Compared

July 2026 — Four protocols enabling AI agents to pay for services. All live, processing real transactions.

x402 Open Standard

Backed by: Linux Foundation, Coinbase, AWS, Cloudflare, Stripe, Google, Visa, Mastercard — 40+ members. Foundation launched July 14, 2026.

Settlement: USDC on Base (200ms–2s). 130M+ transactions, $41M+ settled across 14 chains.

How: HTTP 402 Payment Required → agent pays USDC on-chain → retries with proof → gets resource. No accounts, no API keys, no KYC.

Marketplaces: Agentic.Market (Coinbase), minia2a.uk (independent, 150+ services, 6 chains).

MPP Enterprise

Backed by: Stripe, Tempo Labs. Launched March 2026.

Settlement: Hybrid USDC + fiat via Shared Payment Tokens. Sub-second finality on Tempo L1.

Best for: Enterprise, streaming payments, compliance-heavy use cases.

L402 Bitcoin

Backed by: Lightning Labs. Protocol dates to March 2020.

Settlement: Bitcoin Lightning Network (under 1 second).

Bridge: Cinderwright bridges x402 ↔ L402 — 2,800+ services indexed across protocols.

AP2 Enterprise

Backed by: Google.

Settlement: Verifiable Digital Credentials ("Mandates") proving user consent.

Best for: Enterprise, consent-based authorization, identity-first payments.

The reality in July 2026: The rails are standardized and backed by every major payment company. 130M+ real micropayments have been processed. But transaction volumes are small, most activity is experimental, and most "revenue" is agents testing their own infrastructure.

If you are building an AI agent: start with x402 — most open, most marketplaces, zero permission required. Get 500 free credits on minia2a →

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