generated: '2026-09-19'
method: searched
source: https://docs.clix.so/api-reference/overview
derived_from: openapi/clix-so-openapi.yml
docs:
- https://docs.clix.so/api-reference/overview
- https://docs.clix.so/a2a/overview
- https://docs.clix.so/clix-cli
summary:
  types: [apiKey]
  api_key_in: [header]
  oauth2: false
  oidc: false
  mtls: false
  note: >-
    Static API keys throughout. REST needs two headers on every call (project id + key); A2A needs one
    (secret key, from which the project is resolved). Two key TYPES exist — public for client SDKs, secret
    (clix_sk_ prefix) for server-side writes — and the docs are explicit that public keys are rejected on
    /a2a and should not be used for user management, sending or triggering. Keys are issued in the console
    (console.clix.so, login-gated); no OAuth metadata is served on any host.
schemes:
- name: ProjectIdAuth
  type: apiKey
  in: header
  parameter: X-Clix-Project-ID
  description: Project ID for authentication — identifies the project; rate limits are tracked on it.
  required_with: ApiKeyAuth
  surfaces: [REST]
  sources: [openapi/clix-so-openapi.yml, 'https://docs.clix.so/api-reference/overview']
- name: ApiKeyAuth
  type: apiKey
  in: header
  parameter: X-Clix-API-Key
  description: API Key for authentication — public or secret depending on the operation.
  key_types:
  - {kind: public, prefix: not stated, use: 'Client-side SDKs in mobile apps, browsers, or public environments', visibility: Safe to expose}
  - {kind: secret, prefix: clix_sk_, use: 'Server-to-server communication, secure backend operations — user management, message sending, campaign triggering', visibility: Must keep confidential}
  surfaces: [REST]
  sources: [openapi/clix-so-openapi.yml, 'https://docs.clix.so/api-reference/overview']
- name: apiKey (A2A)
  type: apiKey
  in: header
  parameter: X-API-Key
  description: Secret API key for A2A authentication (agent card securitySchemes.apiKey). Secret keys only; public keys are rejected; the project is resolved from the key so no project header is sent.
  surfaces: [A2A — POST https://api.clix.so/a2a]
  sources: [a2a/clix-so-agent-card.json, 'https://docs.clix.so/a2a/overview']
  observed: 'POST /a2a without the header -> 401 text/plain "Missing API key" (2026-09-19)'
- name: none (MCP)
  type: none
  description: Neither MCP server takes a credential — the stdio @clix-so/clix-mcp-server and the Mintlify docs endpoint at https://docs.clix.so/mcp both search public documentation only.
  surfaces: [MCP]
- name: device flow (CLI)
  type: human-login
  description: '`clix login` authenticates the CLI with a Clix account via device flow; `clix logout` removes stored credentials; `clix whoami` shows the user. A developer-session login, not an API scheme.'
  surfaces: [CLI]
  sources: ['https://docs.clix.so/clix-cli']
key_management:
  issued_in: Clix console (https://console.clix.so — every path 307s to /auth/login)
  rotation: 'Docs advise: store keys in environment variables or a secrets manager, rotate, least privilege (public in clients, secret only in trusted backends), audit and revoke unused keys, alert on unusual activity. No rotation API is documented.'
  scopes: none — no scoped or restricted keys beyond the public/secret split
errors:
  '401': 'Verify API key and Project ID are correct and valid. Observed bodies: "Missing project id" (REST), "Missing API key" (A2A).'