# x402

> HTTP-native payment protocol for programmatic stablecoin payments, API monetization, paid content, and agent-to-service commerce.

- Readiness score: **89/100** (score.v2)
- Integration difficulty: medium
- Chains: base, polygon, arbitrum-one
- Categories: payments, agent-commerce, http, stablecoins
- Last verified: 2026-06-03 by composewith.eth research (x402.org, CDP docs, and x402 Foundation GitHub live-verified via WebFetch 2026-06-03) (confidence: high)

## Resources

- docs: https://docs.cdp.coinbase.com/x402/
- sdk: https://github.com/x402-foundation/x402
- template: https://docs.cdp.coinbase.com/x402/quickstart-for-sellers
- support: https://discord.gg/cdp

## Good for

- agentic payments
- paid API access
- pay-per-request commerce
- stablecoin micropayments

## Avoid for

- marketplaces that need built-in dispute resolution, escrow, fulfillment, or inventory management
- payments where card rails, fiat settlement, or buyer chargebacks are required

## Capabilities

### HTTP 402 payment flow (production-ready)
Best for: servers that return payment instructions with HTTP 402, clients and agents that retry with payment headers, paid APIs and digital goods
- x402 covers payment authorization and settlement, not marketplace fulfillment, escrow, returns, or dispute handling.

### Facilitator verification and settlement (production-ready)
Best for: sellers that do not want to run blockchain verification infrastructure, ERC-20 stablecoin settlement, multi-network payment acceptance
- Network, token, facilitator, and transaction-pricing assumptions must be verified before production.

## Composes with

- **erc-8004** (agent_identity_and_trust; supports) — ERC-8004 can provide agent identity, discovery, reputation, and validation around paid x402 service endpoints.
- **lighthouse-storage** (storage; supports) — Lighthouse can store agent-readable manifests, paid-content artifacts, receipts, or service metadata referenced by paid endpoints.
- **goldsky** (indexing_and_data; supports) — Goldsky can index payment, fulfillment, refund, and feedback events for paid service dashboards.

## Known issues

- **x402 does not provide marketplace fulfillment, escrow, returns, or dispute resolution by itself** (medium, confirmed) — workaround: Treat x402 as the payment layer. Pair it with marketplace application logic, indexed listing/payment state, admin controls, and explicit fulfillment/refund policies.
  - source: https://docs.cdp.coinbase.com/x402/ (retrieved 2026-06-03, medium)

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Canonical: https://composewith.eth/protocols/x402 · JSON: https://composewith.eth/protocols/x402.json