x402 vs the other live initiatives in 2026 · static facts, citations below
Open standard? | Yes — open spec, Apache 2.0 | Yes — Apache 2.0 | Yes — open specification | No — proprietary network | No — proprietary network |
Settlement layer Where the money actually moves | On-chain (USDC + others) | Delegated to underlying rails | Card networks via Stripe | Mastercard rails | Visa rails |
Currency / asset | Stablecoins, primarily USDC | Rail-dependent (cards, ACH, crypto) | Card-network supported (USD, EUR, …) | Card-network supported | Card-network supported |
Networks | Solana, Base, Optimism, Polygon, Avalanche, +others | Rail-dependent | None — card rails | None — card rails | None — card rails |
Auth model How agents prove they may pay | Per-request signed receipt | Verifiable mandates / credentials | Shared Payment Tokens (SPTs) | Agentic Tokens (scoped per-agent) | Tokenized credentials, behavioral auth |
Sub-cent micropayments? | Yes — designed for $0.001+ | Depends on rail | No — card minimums apply | No — card minimums apply | No — card minimums apply |
Maturity / status | GA · v2 of spec live | v0.2 · Sep 2025 launch · 60+ partners | Powers ChatGPT Instant Checkout (live) | Pilot → expanding partners | Production via partner pilots; mainstream targeted 2026 |
Governance | x402 Foundation (Linux Foundation) | Google-led with industry coalition | Stripe-led, multi-PSP adoption | Mastercard + acquirers | Visa + LLM platforms (Anthropic, OpenAI, Microsoft) |
Best for | Open, programmable, multi-chain agent commerce | Cross-rail credential & mandate delegation | In-chat purchases from existing merchants | Card-based AI shopping with network-grade fraud controls | Card-based AI shopping with issuer-side authentication |
Each cell is a fact, sourced from the upstream maintainer's own announcement or documentation. Cells are color-coded only where there is an unambiguous difference between protocols — open vs closed, supports vs doesn't support micropayments. We don't score “winners”; we surface the trade-offs. The protocols solve overlapping but not identical problems.
Three of these are not direct competitors: AP² is a credential-delegation layer that can run on top of any settlement rail (including x402). ACP and Stripe's Shared Payment Tokens replace card credentials with scoped tokens for in-chat checkout. Mastercard Agent Pay and Visa Intelligent Commerce are network-side token systems that work alongside their existing card rails. x402 is the only one that settles on-chain in stablecoins.