Synthflow Authentication

generated: '2026-08-13'
method: searched
source: https://docs.synthflow.ai/authentication
docs: https://docs.synthflow.ai/authentication
derived_from: openapi/_original/synthflow-openapi.json
description: >-
  Synthflow runs two different authentication models on two different surfaces. The REST
  Platform API uses a single static workspace API key sent as an HTTP bearer token. The
  hosted MCP server uses OAuth 2.0, delegated to WorkOS AuthKit, with dynamic client
  registration and PKCE. They do not share credentials.

summary:
  types: [http, oauth2]
  api_key_in: [header]
  oauth2_flows: [authorizationCode, deviceCode, refreshToken]
  surfaces: 2

schemes:
  - name: sec0
    surface: rest
    type: http
    scheme: bearer
    header: Authorization
    format: 'Bearer <SYNTHFLOW_API_KEY>'
    sources: [openapi/_original/synthflow-openapi.json]
    applied_to: '100 of 100 operations (global security requirement)'
    key_prefix: none
    key_management: 'Admin -> Workspace Settings -> API Keys'
    scoping: workspace
    role_gated: 'Key creation and viewing depend on the user role.'
    mfa_prerequisite: 'Where the workspace requires 2FA, a user must have 2FA enabled to create or view API keys.'
    rotation_guidance: 'Provider advises rotating keys periodically and deleting unused keys.'
    verification: >-
      Synthflow publishes a read-only verification call — GET
      https://api.synthflow.ai/v2/assistants/ (list-assistant) takes no required
      parameters, so a 200 confirms the key.
    expiry: 'Not documented — keys appear to be long-lived until deleted.'
    scopes: none
    note: >-
      A single static key carries full workspace authority across all 100 operations,
      including delete-assistant and voice-call (which places real, billable calls). There
      is no read-only key, no per-resource scoping and no key-level permission model, so an
      agent given a key to read call logs can also delete every agent in the workspace.
  - name: mcp-oauth
    surface: mcp
    type: oauth2
    resource: https://mcp.synthflow.ai/mcp
    protected_resource_metadata: https://mcp.synthflow.ai/.well-known/oauth-protected-resource
    authorization_server: https://kind-prelude-27.authkit.app
    authorization_server_metadata: https://kind-prelude-27.authkit.app/.well-known/oauth-authorization-server
    issuer: https://kind-prelude-27.authkit.app
    bearer_methods_supported: [header]
    flows:
      - flow: authorizationCode
        authorizationUrl: https://kind-prelude-27.authkit.app/oauth2/authorize
        tokenUrl: https://kind-prelude-27.authkit.app/oauth2/token
        pkce: S256
      - flow: deviceCode
        deviceAuthorizationUrl: https://kind-prelude-27.authkit.app/oauth2/device_authorization
        grant_type: 'urn:ietf:params:oauth:grant-type:device_code'
      - flow: refreshToken
        tokenUrl: https://kind-prelude-27.authkit.app/oauth2/token
    dynamic_client_registration: https://kind-prelude-27.authkit.app/oauth2/register
    introspection_endpoint: https://kind-prelude-27.authkit.app/oauth2/introspection
    jwks_uri: https://kind-prelude-27.authkit.app/oauth2/jwks
    token_endpoint_auth_methods_supported: [none, client_secret_post, client_secret_basic]
    response_types_supported: [code]
    response_modes_supported: [query]
    scopes: [openid, profile, email, offline_access]
    see: scopes/synthflow-scopes.yml
    provenance_note: >-
      kind-prelude-27.authkit.app is a WorkOS AuthKit tenant, not a synthflow.ai host. It
      is named as the authorization server by Synthflow's OWN protected-resource metadata
      served from mcp.synthflow.ai, and Synthflow's security documentation independently
      states that WorkOS is its identity infrastructure provider. This is a delegated IdP,
      not a foreign contract.
  - name: docs-mcp
    surface: mcp-docs
    type: none
    url: https://docs.synthflow.ai/_mcp/server
    note: 'The Fern documentation MCP server answers initialize and tools/list anonymously.'

workspace_authentication:
  description: 'How humans sign in, as distinct from how API callers authenticate.'
  docs: https://docs.synthflow.ai/security
  methods:
    - {method: email-password, mfa: 'TOTP 2FA with backup codes, optionally mandatory workspace-wide'}
    - {method: google, mfa: 'TOTP 2FA'}
    - {method: sso-saml, provider: WorkOS, plan: Enterprise, identity_providers: [Okta, Entra ID, Google SAML, Auth0]}
  allowed_email_domains: true

webhook_authentication:
  direction: inbound-to-customer
  mechanism: HMAC-SHA256
  header: HTTP_SYNTHFLOW_SIGNATURE
  see: asyncapi/synthflow-webhooks.yml

gaps:
  - 'No scoped or read-only API keys — one key, full workspace authority.'
  - 'No documented key expiry or automatic rotation.'
  - 'No OAuth on the REST API, so a third-party integration must hold a customer''s raw workspace key.'
  - 'No /.well-known/openid-configuration on any synthflow.ai host.'

x-evidence:
  fetched: '2026-08-13'
  probes:
    - {url: 'https://docs.synthflow.ai/authentication.md', status: 200}
    - {url: 'https://mcp.synthflow.ai/mcp', status: 401, detail: 'WWW-Authenticate: Bearer error="unauthorized"'}
    - {url: 'https://mcp.synthflow.ai/.well-known/oauth-protected-resource', status: 200}
    - {url: 'https://kind-prelude-27.authkit.app/.well-known/oauth-authorization-server', status: 200}