Receiving Webhooks

When you send a Programmable Fax command and receive a successful response (i.e. 200 OK), you can expect to receive a webhook. The webhook will be delivered to the primary URL specified on the Application associated with the call. If that URL does not resolve, or your application returns a non 200 OK response, the webhook will be delivered to the failover URL, if one has been specified.

In order to minimize webhook delivery time, Telnyx:

  • does not enforce the order in which webhooks are delivered
  • retries webhook delivery if your application does not respond within a certain time threshold.

As a result, you may encounter:

  • out-of-order webhooks
  • simultaneous (or near simultaneous) webhooks
  • duplicate webhooks

Duplicate webhooks may cause your application to issue duplicate commands. You can instruct Telnyx to ignore duplicate commands by sending a command_id parameter as part of your commands. Commands with duplicate command_ids within 60 seconds will be ignored.

Example: Receiving a webhook from an outbound fax

When you place an outbound fax, you will receive a number of webhooks indicating the current status of the fax. The first webhook you will receive will have A queued status indicating that Telnyx successfully received the request to send the fax.

  "data": {
    "event_type": "fax.queued",
    "id": "3691d047-d22a-424d-80ed-fe871981aa6d",
    "occurred_at": "2020-04-22T19:32:12.538002Z",
    "record_type": "event",
    "payload": {
      "call_duration_secs": 50,
      "connection_id": "7267xxxxxxxxxxxxxx",
      "direction": "outbound",
      "fax_id": "b679398e-8b4c-46bd-8630-6797f1ab5228",
      "from": "+35319605860",
      "original_media_url": "",
      "partial_content": true,
      "status": "queued",
      "to": "+13129457420",
      "user_id": "a5b1dfa3-fd2e-4e02-8ea4-xxxxxxxxxxxx"
  "meta": {
    "attempt": 1,
    "delivered_to": ""
record_typeDescription of the record.
idunique id for the webhook
event_typeThe type of event
occured_atISO-8601 datetime of when event was created
toDestination number or SIP URI of the call
fromNumber or SIP URI placing the call
fax_idUnique ID for the Programmable Fax
client_stateConfigurable state to track commands
statusCan be one of queued, media.processed, sending.started, delivered, failed

Example: Receiving a webhook on successful fax delivery

  "event_type": "fax.delivered",
  "id": "3320554f-6b74-4138-a74b-a1e2ec7eaf8b",
  "occurred_at": "2022-01-07T10:01:43.677850Z",
  "payload": {
    "call_duration_secs": 79,
    "connection_id": "1232154810234",
    "direction": "outbound",
    "fax_id": "c62be5bc-9b13-4b6c-abda-34dd8b541287",
    "from": "+19459457421",
    "original_media_url": "",
    "page_count": 1,
    "status": "delivered",
    "to": "+13129457420",
    "user_id": "bdaa1f9f-1018-4156-867d-6c4ac9f556eb"

Example: Receiving a webhook on failed fax delivery

  "event_type": "fax.failed",
  "id": "d906ecda-db21-428e-9ca0-74dae7e7c144",
  "occurred_at": "2022-01-05T22:23:46.888808Z",
  "payload": {
    "connection_id": "1232154810234",
    "direction": "outbound",
    "failure_reason": "user_busy",
    "fax_id": "f7b303ed-674c-4962-951b-848380510893",
    "from": "+19459457421",
    "original_media_url": "",
    "status": "failed",
    "to": "+13129457420",
    "user_id": "417b0cc2-39e0-4ab9-b116-e56543649aa9"

Possible failure reasons

Inspect the failure_reason field in webhook's payload to debug failed deliveries of your faxes. The possible failure reasons are:

  • account_disabled
  • connection_channel_limit_exceeded
  • destination_invalid
  • destination_not_in_countries_whitelist
  • destination_not_in_service_plan
  • destination_unreachable
  • fax_signaling_error
  • invalid_ecm_response_from_receiver
  • no_outbound_profile
  • outbound_profile_channel_limit_exceeded
  • outbound_profile_daily_spend_limit_exceeded
  • receiver_call_dropped
  • receiver_communication_error
  • receiver_decline
  • receiver_incompatible_destination
  • receiver_invalid_number_format
  • receiver_no_answer
  • receiver_no_response
  • receiver_recovery_on_timer_expire
  • receiver_unallocated_number
  • service_unavailable
  • user_busy
  • user_channel_limit_exceeded
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