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Webhook

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Definition

A Webhook is a mechanism that allows you to receive real-time notifications about faxes being sent and received.

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Setting Up Webhooks

To start receiving real-time updates, you need to create a webhook in the Fax.Plus system. Here’s how:
  1. Decide on a target URL where you want to receive webhook notifications. This should be an endpoint on your server that’s set up to handle incoming POST requests.
  2. Choose the event(s) you want to track. Fax.Plus offers the following webhook events:
  • fax_sent — When a fax is successfully sent
  • fax_received — When a fax is successfully received
  • fax_page_received — When a single page of a fax is received (requires fax streaming, available on request)
  1. Use the Fax.Plus API to create the webhook. You’ll need to specify your target URL and the event(s) you want to track.
For detailed information on how to create a webhook using the API, refer to the Register a webhook endpoint documentation.

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Handling Webhook Notifications

Once you’ve set up your webhook, Fax.Plus will send POST requests to your specified URL whenever the tracked events occur. Here’s what you need to know about handling these notifications:
  • Request Method: All webhook notifications are sent as HTTP POST requests.
  • Payload Structure: The webhook payload is a JSON object containing two main sections:
  • hook: Contains metadata about the webhook itself.
  • data: Contains information about the fax that triggered the event.

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Events

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fax_sent

The fax_sent event is triggered when a fax is successfully sent.
fax_sent payload
{
    "hook": {
        "id": "66df09cf1d6d0b295c363956",
        "event": "fax_sent",
        "event_time": "2024-09-09 10:44:39",
        "target": "https://webhook.com"
    },
    "data": {
        "id": "66df09cf1d6d0b295c363956",
        "uid": "490ae330dbc749f0b6561dafa300f2fb",
        "pages": 1,
        "from": "+1 334-304-xxxx",
        "to": "+1 334-304-xxxx",
        "start_time": "2024-09-09 10:44:39",
        "file": "1d0b618e4fb54957878eed0ecc64ae5e.tiff",
        "file_name": "fax-to-1334304xxxx",
        "status": "success",
        "cost": 1
    }
}
If hook.id is not equal to data.id, the fax is being retried. If hook.id equals data.id, it indicates the fax is being sent for the first time.

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Payload schema

NameTypeRequiredDescription
hookobjectYesHook and event description
idstringYesFax ID
eventstringYesEvent type
event_timestringYesTime of the event. Format: YYYY-MM-DD HH:mm:ss
targetstringYesConfigured URL target for this webhook
dataobjectYesCallback data, depends on the event type
idstringYesFax session ID. This ID might differ from the one returned by listFaxes
uidstringYesSender user ID
pagesnumberYesNumber of pages in the fax
fromstringYesSender number. Might be a user ID for faxes sent from free accounts
tostringYesFax destination number. Might be a user ID for faxes sent from free accounts
start_timestringYesTime at which faxing session started. Format: YYYY-MM-DD HH:mm:ss
filestringYesFile ID
file_namestringYesHuman-readable file name
costnumberYesFax cost (in pages)
statusFaxStatusYesFax status

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fax_received

The fax_received event is triggered when a fax is successfully received.
fax_received payload
{
    "hook": {
        "id": "9b0cfcad-5bf8-41ff-94f7-eb5b1b85a0bf",
        "event": "fax_received",
        "event_time": "2024-09-09 12:44:39",
        "target": "https://webhook.com"
    },
    "data": {
        "id": "9b0cfcad-5bf8-41ff-94f7-eb5b1b85a0bf",
        "uid": "490ae330dbc749f0b6561dafa300f2fb",
        "pages": 1,
        "from": "+1 334-304-xxxx",
        "to": "+1 334-304-xxxx",
        "start_time": "2024-09-09 12:44:39",
        "file": "27ade44579274f01b55e552cd361990e.tiff",
        "file_name": "fax-from-1334304xxxx",
        "status": "success",
        "cost": 1
    }
}

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Payload schema

The payload schema for fax_received is identical to the fax_sent event.

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fax_page_received

The fax_page_received event is only available if your account has fax streaming enabled. This feature is available on request — contact us to discuss enabling it for your account.
The fax_page_received event is triggered when a single page of a fax is received. This event is only sent when fax streaming is enabled, allowing you to process pages as they arrive rather than waiting for the complete fax.
fax_page_received payload
{
    "hook": {
        "id": "9b0cfcad-5bf8-41ff-94f7-eb5b1b85a0bf",
        "event": "fax_page_received",
        "event_time": "2024-09-09 12:44:39",
        "target": "https://webhook.com"
    },
    "data": {
        "id": "9b0cfcad-5bf8-41ff-94f7-eb5b1b85a0bf",
        "page": 1,
        "from": "+1 334-304-xxxx",
        "to": "+1 334-304-xxxx"
    }
}

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Payload schema

NameTypeRequiredDescription
hookobjectYesHook and event description
idstringYesFax session ID
eventstringYesEvent type
event_timestringYesTime of the event. Format: YYYY-MM-DD HH:mm:ss
targetstringYesConfigured URL target for this webhook
dataobjectYesCallback data for the page received event
idstringYesFax session ID
pagenumberYesPage number that was received (starting from 1)
fromstringYesSender number. Might be a user ID for faxes sent from free accounts
tostringYesFax destination number. Might be a user ID for faxes sent from free accounts

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Verify origin IP addresses

To ensure that the webhook requests you receive are legitimate and originate from Fax.Plus, it’s important to verify the IP addresses. Fax.Plus webhooks will only be sent from the following authorized IP addresses:
  • 34.65.253.117
  • 34.65.146.131
Make sure your server is configured to accept webhook requests only from these IPs to enhance security.

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Handling the Notification

When your server receives a webhook notification:
  1. Verify the payload to ensure it’s a valid webhook notification.
  2. Extract the relevant information from the payload.
  3. Perform any necessary actions based on the event type (e.g., update your database, notify users, trigger other processes).
  4. Send a 200 OK response to acknowledge receipt of the webhook.

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Best Practices

  • Security: Ensure your webhook endpoint is secure. Consider implementing authentication for your webhook URL.
  • Idempotency: Design your webhook handler to be idempotent. This means it should produce the same result even if the same webhook is received multiple times.
  • Error Handling: Implement robust error handling in your webhook processing logic.
By following this guide, you’ll be able to set up and handle webhooks effectively, allowing your application to receive real-time updates about fax statuses in the Fax.Plus system.