generated: '2026-10-07'
method: searched
source: https://s1.dev/docs/essentials/authentication; https://s1.dev/auth.md; https://clerk.s1.dev/.well-known/oauth-authorization-server;
  openapi/s1-dev-openapi.yml
docs: https://s1.dev/docs/essentials/authentication
summary:
  types:
  - http
  - oauth2
  - payment-challenge
  header: 'Authorization: Bearer <token-or-key>'
schemes:
- name: bearerAuth
  type: http
  scheme: bearer
  bearerFormat: API Key
  description: 'User-managed API key created in https://app.s1.dev, sent as Authorization: Bearer. The hosted MCP
    server also accepts ?apiKey= for clients that cannot send headers (header wins).'
  sources:
  - openapi/s1-dev-openapi.yml
- name: oauth2
  type: oauth2
  flows:
    authorizationCode:
      authorizationUrl: https://clerk.s1.dev/oauth/authorize
      tokenUrl: https://clerk.s1.dev/oauth/token
      refreshUrl: https://clerk.s1.dev/oauth/token
      scopes:
        openid: identity
        offline_access: refresh token
  issuer: https://clerk.s1.dev
  registration_endpoint: https://clerk.s1.dev/oauth/register
  revocation_endpoint: https://clerk.s1.dev/oauth/token/revoke
  pkce:
  - S256
  grant_types:
  - authorization_code
  - refresh_token
  - urn:ietf:params:oauth:grant-type:device_code
  description: 'OAuth 2.1 for agents, OAuth-aware MCP clients and the s1 CLI: dynamic client registration, authorization
    code + PKCE S256, refresh with offline_access. Discovery starts at the protected-resource metadata (RFC 9728)
    of api.search1api.com or mcp.search1api.com.'
  protected_resources:
  - https://api.search1api.com
  - https://mcp.search1api.com/mcp
  sources:
  - https://s1.dev/auth.md
- name: paymentChallenge
  type: payment
  description: 'Pay-per-request: a call without a bearer token receives 402 application/problem+json with a WWW-Authenticate:
    Payment challenge (MPP, method="tempo"); the spec names MPP and x402.'
  sources:
  - https://s1.dev/docs/essentials/error-handling
  - live POST https://api.search1api.com/search 2026-10-07