Authentication

All JDay API endpoints require authentication via API key.

Header Format

Send your API key in the Authorization header:

Authorization: Bearer YOUR_API_KEY

API keys are opaque and case-sensitive. All requests must use HTTPS.

Example Request

curl -X GET "https://jday-api.jday.workers.dev/v1/is-business-day?date=2026-04-03&country=ZA" \
  -H "Authorization: Bearer jday_live_xxx" \
  -H "Accept: application/json"

Authentication Failures

All of the following return 401 unauthorized with the same response shape:

• Missing bearer token
• Wrong auth scheme
• Unknown key
• Revoked key
• Disabled key
• Expired key
• Structurally invalid key

{
  "error": {
    "code": "unauthorized",
    "message": "Valid API authentication is required."
  },
  "request_id": "018f7d1a-3a51-7f4b-9c78-830f8b6ce220"
}

The 401 response always includes:

WWW-Authenticate: Bearer realm="JDay"

The API will never leak whether a specific key previously existed. All invalid credentials return the same status and message.

Request Tracing

Every response includes an X-Request-Id header containing a server-generated UUIDv7:

X-Request-Id: 018f7d1a-3a51-7f4b-9c78-830f8b6ce220

You can optionally send X-Client-Request-Id for your own trace correlation. JDay echoes it back only if it is 1–128 printable ASCII characters with no control characters. Invalid values are silently ignored.

request_id is for debugging and support — it has no billing semantics.