# Relay

> Verified agent commerce infrastructure for Stellar x402 services. Relay adds discovery, active verification, policy-aware routing, and publicly verifiable receipts on top of standard x402 payments.

Relay is not a wallet, a facilitator, or a new protocol. Payment payloads stay wire-compatible x402; Relay is the layer an autonomous buyer needs before and after the payment.

## Live environment

- Base URL: https://api.relayx402.xyz
- Network: stellar:testnet
- Protocol: x402 v2
- Schemes: exact, upto (availability depends on the configured facilitators)
- Asset: USDC (Stellar Asset Contract, 7 decimals)

## Start here

- [Quickstart](https://api.relayx402.xyz/docs#quickstart): Discover, route, and pay for a real x402 resource.
- [Overview](https://api.relayx402.xyz/docs#overview): What Relay does and does not do.
- [OpenAPI specification](https://api.relayx402.xyz/openapi.json): Full machine-readable API description.

## Concepts

- [Verification](https://api.relayx402.xyz/docs#verification): How probes become reliability, confidence, and verification levels. Metrics are computed from recorded observations; a resource with no evidence reports zero confidence rather than a placeholder.
- [Routing and policy](https://api.relayx402.xyz/docs#routing): Deterministic provider selection with a reason code for every rejection. Spend caps are evaluated against worst-case spend, so an `upto` ceiling cannot exceed an agent's limit.
- [Receipts](https://api.relayx402.xyz/docs#receipts): Ed25519-signed records linking intent, route, payment, and response hash. Verifiable by anyone holding the receipt.
- [Facilitators](https://api.relayx402.xyz/docs#facilitator): Relay routes verify/settle across multiple facilitator backends with health-aware failover.

## API reference

- [GET /health/live](https://api.relayx402.xyz/health/live): Liveness.
- [GET /health/ready](https://api.relayx402.xyz/health/ready): Readiness, network, and settlement asset.
- [GET /health/dependencies](https://api.relayx402.xyz/health/dependencies): Store durability and facilitator health.
- [GET /x402/supported](https://api.relayx402.xyz/x402/supported): Supported payment kinds, merged across facilitators.
- [POST /x402/verify](https://api.relayx402.xyz/docs#facilitator): Verify a payment payload without settling.
- [POST /x402/settle](https://api.relayx402.xyz/docs#facilitator): Settle a verified payment.
- [GET /x402/facilitators](https://api.relayx402.xyz/x402/facilitators): Per-backend facilitator health.
- [GET /v1/resources](https://api.relayx402.xyz/v1/resources): List catalogued machine-payable resources.
- [GET /v1/resources/:id](https://api.relayx402.xyz/docs#discovery): Resolve one resource with its metrics.
- [POST /v1/search](https://api.relayx402.xyz/docs#discovery): Search by capability, network, asset, scheme, and price.
- [POST /v1/validate](https://api.relayx402.xyz/docs#verification): Probe an endpoint and record the observation.
- [GET /v1/resources/:id/metrics](https://api.relayx402.xyz/docs#verification): Metrics computed from real observations.
- [GET /v1/resources/:id/observations](https://api.relayx402.xyz/docs#verification): The raw evidence behind the metrics.
- [POST /v1/routes](https://api.relayx402.xyz/docs#routing): Rank eligible providers under a policy.
- [POST /v1/policies/evaluate](https://api.relayx402.xyz/docs#routing): Dry-run a policy against one resource.
- [POST /v1/receipts](https://api.relayx402.xyz/docs#receipts): Create a signed commerce receipt.
- [GET /v1/receipts/signer](https://api.relayx402.xyz/v1/receipts/signer): The Ed25519 public key receipts are signed with.
- [GET /v1/receipts/:id/verify](https://api.relayx402.xyz/docs#receipts): Verify a receipt's signature.

## MCP

Relay exposes an MCP server mirroring the HTTP surface: `search_resources`, `get_resource`, `validate_endpoint`, `route_resource`, `get_resource_health`, `get_resource_metrics`.

## Optional

- [x402 protocol](https://www.x402.org/)
- [Stellar developer docs](https://developers.stellar.org/)
- [Atlas RWA intelligence](https://atlas.relayx402.xyz/)