generated: '2026-07-18'
method: searched
source: https://docs.trychert.com/api/authentication
docs: https://docs.trychert.com/api/authentication
summary:
  types: [http, hmac]
  api_key_in: [header]
  transport_requirement: TLS 1.2+
schemes:
- name: BearerToken
  type: http
  scheme: bearer
  header: authorization
  format: "Bearer <signing_secret>"
  notes: >-
    Simplest method for scripts, prototypes, and trusted server-to-server calls.
    Signing secret is a 32-char hex value revealed once in the Chert console; server
    uses constant-time comparison.
- name: HMAC-SHA256
  type: hmac
  algorithm: HMAC-SHA256
  header: x-chert-signature
  header_format: "v1,<unix_seconds>,<hmac_hex>"
  signing_string: "<unix_seconds>.<raw_body>"
  raw_body_rules:
  - POST uses the exact transmitted bytes (no re-serialization)
  - GET uses an empty string (signature ends with a trailing dot)
  replay_window_seconds: 300
  recommended_for: exposed environments (edge functions, client-side code)
required_headers:
- name: x-chert-tenant
  value: tenant_slug from registration
  required_when: with HMAC signatures or for multi-tenant accounts
- name: content-type
  value: application/json
  required_when: POST requests
key_management:
  issuance: Signing secret displayed once at registration via the Chert console
  rotation: Requires contacting a Chert administrator (API keys page -> Reveal/rotate)
  re_registration: Re-registering the same email returns the existing tenant without regeneration
webhook_signing:
  scheme: HMAC-SHA256
  note: >-
    Webhook deliveries use a separate per-subscription secret, computed identically as
    HMAC-SHA256(subscription_secret, "<ts>.<raw_body>"). Do not use the API signing secret
    to verify webhooks.