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
  3. 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

NameTypeRequiredDescriptionRestrictions
hookobjectYesHook and event descriptionnone
idstringYesFax IDnone
eventstringYesEvent typenone
event_timestringYesTime of the event. Format: YYYY-MM-DD HH:mm:ssnone
targetstringYesConfigured URL target for this webhooknone
dataobjectYesCallback data, depends on the event typenone
idstringYesFax session ID. This ID might differ from the one returned by listFaxesnone
uidstringYesSender user IDnone
pagesnumberYesNumber of pages in the faxnone
fromstringYesSender number. Might be a user ID for faxes sent from free accountsnone
tostringYesFax destination number. Might be a user ID for faxes sent from free accountsnone
start_timestringYesTime at which faxing session started. Format: YYYY-MM-DD HH:mm:ssnone
filestringYesFile IDnone
file_namestringYesHuman-readable file namenone
costnumberYesFax cost (in pages)none
statusFaxStatusYesFax statusnone

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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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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.