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API discovery lets agents and marketplaces learn what your API costs and how to pay before they call a protected route. Proceeds generates OpenAPI 3.1 discovery documents from your service and paywall configuration. Discovery targets two ecosystems:
  • MPP discovery — Machine Payments Protocol registries and clients
  • x402scan — x402 service discovery and indexing

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Why it matters

Without discovery, an agent only learns your price after hitting 402. With discovery, it can:
  • Find your endpoints in a registry
  • Read price, currency, and payment methods upfront
  • Follow docs and guidance you publish for successful calls
If you sell to agents, treat discovery as part of go-to-market — same as a public OpenAPI spec for a free API.

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Documents Proceeds publishes

Registries resolve the per-service subdomain documents: Path aliases return the same documents:
  • https://myproceeds.xyz/api/x402/pay/{serviceId}/openapi.json
  • https://myproceeds.xyz/api/mpp/pay/{serviceId}/openapi.json
The MPP document 404s if the service has no Tempo-enabled paywalls. x402-only services only get the x402 root.
https://myproceeds.xyz/openapi.json is a platform-wide aggregate, not the URL you register as a provider. Providers register the per-service subdomain doc with x402scan, MPPScan, or the MPP directory. Payment URLs for individual paywalls stay the same:
See Payment URLs.

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What you configure in the dashboard

On the service overflow menu, open Advertise and fill in: Proceeds auto-drafts Agent guidance on service create (and as a fallback) from your paywall names and descriptions. Review it before saving — clear guidance reduces failed paid calls. Only enabled paywalls are listed in the discovery document.

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What agents see

Discovery documents include payment metadata such as:
  • Endpoint paths and HTTP methods
  • Price and currency (USDC)
  • Supported networks and payment methods (x402 and/or Tempo / MPP)
Tempo-only paywalls appear in MPP discovery; EVM paywalls appear in x402 discovery. A service that supports both can show up in both ecosystems.

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Publish and validate

  1. Save Advertise metadata and enable the paywalls you want listed.
  2. Fix live validation errors in the Advertise drawer.
  3. Copy the subdomain openapi.json URL(s) from the drawer.
  4. Register with MPPScan, the MPP directory, and/or x402scan. In-app registry links stay gated until the discovery document validates.
Keep paywall names and descriptions accurate — they feed both human docs and auto-drafted agent guidance.

MPP discovery spec

How MPP clients expect OpenAPI payment terms.

x402scan discovery

Browse and publish x402-compatible APIs.