fax.sending

Sent when a delivery attempt against the destination begins.

WEBHOOK fax.sending

Example

{
  "id": "evt_8aZqRm4yT3vK7pNxJ2bH9c",
  "created": 123,
  "data": {
    "object": {
      "id": "<string>",
      "to": "<string>",
      "pages": 123,
      "error_code": "<string>",
      "error_subcode": "<string>",
      "error_message": "<string>",
      "max_attempts": 3,
      "attempts": [
        {
          "attempt_number": 2,
          "started_at": "2023-11-07T05:31:56Z",
          "completed_at": "2023-11-07T05:31:56Z",
          "duration_ms": 123,
          "error_code": "<string>",
          "error_subcode": "<string>",
          "error_message": "<string>"
        }
      ],
      "webhook_url": "<string>",
      "idempotency_key": "<string>",
      "tags": {},
      "csid": "<string>",
      "submitted_at": "2023-11-07T05:31:56Z",
      "completed_at": "2023-11-07T05:31:56Z",
      "created_at": "2023-11-07T05:31:56Z",
      "updated_at": "2023-11-07T05:31:56Z"
    }
  }
}

When it fires

At the start of each delivery attempt against the destination. A fax that retries on a transient failure will fire fax.sending again before the next attempt.

The current attempt is recorded in attempts[] with started_at set and completed_at null. Previous attempts (if any) are also present with their full detail.

What your handler should do

• Use this for in-flight visibility - “fax is currently being sent.”
• If you display fax status to your users, this is the event that moves the display from “queued” to “in progress.”
• Do not finalize success or failure on this event. Wait for fax.delivered or fax.failed.

The number of fax.sending events for a single fax depends on how many delivery attempts run, which is bounded by max_attempts (1 to 5, default 3).

Authorizations

Authorization · string · header · required

API key as Bearer token. Use an account key (mfx_acct_...) for /account/* endpoints, and an environment key (mfx_test_... for sandbox, mfx_live_... for live) for /environment/*, /faxes, /webhooks, and /events.

Body

application/json

Event delivery to your subscribed webhook endpoint.

Webhook delivery for fax.sending.

id · string · required

Event identifier (evt_-prefixed). Stable across retry attempts.

Example:

"evt_8aZqRm4yT3vK7pNxJ2bH9c"

type · enum<string> · required

Event type. Always fax.sending for this delivery.

Available options: fax.sending

created · integer · required

Unix epoch seconds when the event was generated.

data · object · required

Show child attributes

Response

2XX

Acknowledged. mintfax treats any 2xx response as a successful delivery.