generated: '2026-07-21'
method: searched
source: https://docs.paysponge.com/llms.txt
derived_from: openapi/sponge-openapi-original.json
description: >-
  Cross-cutting standards Sponge's public API conforms to, derived from the
  OpenAPI spec and the published docs/skill. Sponge is notable for implementing
  emerging agent-payment standards (x402, MPP) alongside conventional web
  identity standards.
standards:
- id: openapi-3.0
  conforms: true
  evidence: openapi/sponge-openapi-original.json declares openapi 3.0.3
- id: oauth2
  conforms: true
  evidence: >-
    OAuth 2.0 authorization server metadata at
    /.well-known/oauth-authorization-server (authorization_code + refresh_token).
- id: oidc
  conforms: true
  evidence: OpenID Connect discovery at /.well-known/openid-configuration.
- id: oauth-pkce
  conforms: true
  evidence: code_challenge_methods_supported = [S256].
- id: rfc7591-dynamic-client-registration
  conforms: true
  evidence: registration_endpoint advertised in OAuth server metadata.
- id: rfc9727-api-catalog
  conforms: true
  evidence: /.well-known/api-catalog linkset published on docs.paysponge.com.
- id: eip-4361-siwe
  conforms: true
  evidence: POST /api/siwe/generate and `spongewallet auth siwe` for EIP-4361 signatures.
- id: x402-payments
  conforms: true
  evidence: POST /api/x402/fetch; x402 USDC payment protocol for paid endpoints.
- id: mpp-payments
  conforms: true
  evidence: POST /api/mpp/fetch and MPP session endpoints (Tempo).
- id: rfc9457-problem-details
  conforms: false
  evidence: No application/problem+json responses documented in the OpenAPI spec.
- id: rfc8594-sunset-header
  conforms: false
- id: fapi
  conforms: false