Telnyx Fax - Python

Installation

pip install telnyx

Setup

import os from telnyx import Telnyx

client = Telnyx( api_key=os.environ.get("TELNYX_API_KEY"), # This is the default and can be omitted )

All examples below assume client is already initialized as shown above.

Error Handling

All API calls can fail with network errors, rate limits (429), validation errors (422), or authentication errors (401). Always handle errors in production code:

import telnyx

try: result = client.messages.send(to="+13125550001", from_="+13125550002", text="Hello") except telnyx.APIConnectionError: print("Network error — check connectivity and retry") except telnyx.RateLimitError: # 429: rate limited — wait and retry with exponential backoff import time time.sleep(1) # Check Retry-After header for actual delay except telnyx.APIStatusError as e: print(f"API error {e.status_code}: {e.message}") if e.status_code == 422: print("Validation error — check required fields and formats")

Common error codes: 401 invalid API key, 403 insufficient permissions, 404 resource not found, 422 validation error (check field formats), 429 rate limited (retry with exponential backoff).

Important Notes

Phone numbers must be in E.164 format (e.g., +13125550001 ). Include the + prefix and country code. No spaces, dashes, or parentheses.
Pagination: List methods return an auto-paginating iterator. Use for item in page_result: to iterate through all pages automatically.

List all Fax Applications

This endpoint returns a list of your Fax Applications inside the 'data' attribute of the response. You can adjust which applications are listed by using filters. Fax Applications are used to configure how you send and receive faxes using the Programmable Fax API with Telnyx.

GET /fax_applications

page = client.fax_applications.list() page = page.data[0] print(page.id)

Returns: active (boolean), anchorsite_override (enum: Latency, Chicago, IL, Ashburn, VA, San Jose, CA, Sydney, Australia, Amsterdam, Netherlands, London, UK, Toronto, Canada, Vancouver, Canada, Frankfurt, Germany), application_name (string), created_at (string), id (string), inbound (object), outbound (object), record_type (string), tags (array[string]), updated_at (string), webhook_event_failover_url (uri), webhook_event_url (uri), webhook_timeout_secs (integer | null)

Creates a Fax Application

Creates a new Fax Application based on the parameters sent in the request. The application name and webhook URL are required. Once created, you can assign phone numbers to your application using the /phone_numbers endpoint.

POST /fax_applications — Required: application_name , webhook_event_url

Optional: active (boolean), anchorsite_override (enum: Latency, Chicago, IL, Ashburn, VA, San Jose, CA, Sydney, Australia, Amsterdam, Netherlands, London, UK, Toronto, Canada, Vancouver, Canada, Frankfurt, Germany), inbound (object), outbound (object), tags (array[string]), webhook_event_failover_url (uri), webhook_timeout_secs (integer | null)

fax_application = client.fax_applications.create( application_name="fax-router", webhook_event_url="https://example.com", ) print(fax_application.data)

Retrieve a Fax Application

Return the details of an existing Fax Application inside the 'data' attribute of the response.

GET /fax_applications/{id}

fax_application = client.fax_applications.retrieve( "1293384261075731499", ) print(fax_application.data)

Update a Fax Application

Updates settings of an existing Fax Application based on the parameters of the request.

PATCH /fax_applications/{id} — Required: application_name , webhook_event_url

Optional: active (boolean), anchorsite_override (enum: Latency, Chicago, IL, Ashburn, VA, San Jose, CA, Sydney, Australia, Amsterdam, Netherlands, London, UK, Toronto, Canada, Vancouver, Canada, Frankfurt, Germany), fax_email_recipient (string | null), inbound (object), outbound (object), tags (array[string]), webhook_event_failover_url (uri), webhook_timeout_secs (integer | null)

fax_application = client.fax_applications.update( id="1293384261075731499", application_name="fax-router", webhook_event_url="https://example.com", ) print(fax_application.data)

Deletes a Fax Application

Permanently deletes a Fax Application. Deletion may be prevented if the application is in use by phone numbers.

DELETE /fax_applications/{id}

fax_application = client.fax_applications.delete( "1293384261075731499", ) print(fax_application.data)

View a list of faxes

GET /faxes

page = client.faxes.list() page = page.data[0] print(page.id)

Returns: client_state (string), connection_id (string), created_at (date-time), direction (enum: inbound, outbound), from (string), from_display_name (string), id (uuid), media_name (string), media_url (string), preview_url (string), quality (enum: normal, high, very_high, ultra_light, ultra_dark), record_type (enum: fax), status (enum: queued, media.processed, originated, sending, delivered, failed, initiated, receiving, media.processing, received), store_media (boolean), stored_media_url (string), to (string), updated_at (date-time), webhook_failover_url (string), webhook_url (string)

Send a fax

Send a fax. Files have size limits and page count limit validations. If a file is bigger than 50MB or has more than 350 pages it will fail with file_size_limit_exceeded and page_count_limit_exceeded respectively.

POST /faxes — Required: connection_id , from , to

Optional: black_threshold (integer), client_state (string), from_display_name (string), media_name (string), media_url (string), monochrome (boolean), preview_format (enum: pdf, tiff), quality (enum: normal, high, very_high, ultra_light, ultra_dark), store_media (boolean), store_preview (boolean), t38_enabled (boolean), webhook_url (string)

fax = client.faxes.create( connection_id="234423", from_="+13125790015", to="+13127367276", ) print(fax.data)

View a fax

GET /faxes/{id}

fax = client.faxes.retrieve( "182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e", ) print(fax.data)

Delete a fax

DELETE /faxes/{id}

client.faxes.delete( "182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e", )

Cancel a fax

Cancel the outbound fax that is in one of the following states: queued , media.processed , originated or sending

POST /faxes/{id}/actions/cancel

response = client.faxes.actions.cancel( "182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e", ) print(response.data)

Returns: result (string)

Refresh a fax

Refreshes the inbound fax's media_url when it has expired

POST /faxes/{id}/actions/refresh

response = client.faxes.actions.refresh( "182bd5e5-6e1a-4fe4-a799-aa6d9a6ab26e", ) print(response.data)

Returns: result (string)

Webhooks

Webhook Verification

Telnyx signs webhooks with Ed25519. Each request includes telnyx-signature-ed25519

and telnyx-timestamp headers. Always verify signatures in production:

In your webhook handler (e.g., Flask — use raw body, not parsed JSON):

@app.route("/webhooks", methods=["POST"]) def handle_webhook(): payload = request.get_data(as_text=True) # raw body as string headers = dict(request.headers) try: event = client.webhooks.unwrap(payload, headers=headers) except Exception as e: print(f"Webhook verification failed: {e}") return "Invalid signature", 400 # Signature valid — event is the parsed webhook payload print(f"Received event: {event.data.event_type}") return "OK", 200

The following webhook events are sent to your configured webhook URL. All webhooks include telnyx-timestamp and telnyx-signature-ed25519 headers for Ed25519 signature verification. Use client.webhooks.unwrap() to verify.

Event Description

fax.delivered

Fax Delivered

fax.failed

Fax Failed

fax.media.processed

Fax Media Processed

fax.queued

Fax Queued

fax.sending.started

Fax Sending Started

Webhook payload fields

fax.delivered

Field Type Description

data.record_type

enum: event Identifies the type of the resource.

data.id

uuid Identifies the type of resource.

data.occurred_at

date-time ISO 8601 datetime of when the event occurred.

data.event_type

enum: fax.delivered The type of event being delivered.

data.payload.call_duration_secs

integer The duration of the call in seconds.

data.payload.connection_id

string The ID of the connection used to send the fax.

data.payload.direction

enum: inbound, outbound The direction of the fax.

data.payload.fax_id

uuid Identifies the fax.

data.payload.original_media_url

string The original URL to the PDF used for the fax's media.

data.payload.media_name

string The media_name used for the fax's media.

data.payload.to

string The phone number, in E.164 format, the fax will be sent to or SIP URI

data.payload.from

string The phone number, in E.164 format, the fax will be sent from.

data.payload.user_id

uuid Identifier of the user to whom the fax belongs

data.payload.page_count

integer Number of transferred pages

data.payload.status

enum: delivered The status of the fax.

data.payload.client_state

string State received from a command.

meta.attempt

integer The delivery attempt number.

meta.delivered_to

uri The URL the webhook was delivered to.

fax.failed

Field Type Description

data.record_type

enum: event Identifies the type of the resource.

data.id

uuid Identifies the type of resource.

data.occurred_at

date-time ISO 8601 datetime of when the event occurred.

data.event_type

enum: fax.failed The type of event being delivered.

data.payload.connection_id

string The ID of the connection used to send the fax.

data.payload.direction

enum: inbound, outbound The direction of the fax.

data.payload.fax_id

uuid Identifies the fax.

data.payload.original_media_url

string The original URL to the PDF used for the fax's media.

data.payload.media_name

string The media_name used for the fax's media.

data.payload.to

string The phone number, in E.164 format, the fax will be sent to or SIP URI

data.payload.from

string The phone number, in E.164 format, the fax will be sent from.

data.payload.user_id

uuid Identifier of the user to whom the fax belongs

data.payload.failure_reason

enum: rejected Cause of the sending failure

data.payload.status

enum: failed The status of the fax.

data.payload.client_state

string State received from a command.

meta.attempt

integer The delivery attempt number.

meta.delivered_to

uri The URL the webhook was delivered to.

fax.media.processed

Field Type Description

data.record_type

enum: event Identifies the type of the resource.

data.id

uuid Identifies the type of resource.

data.occurred_at

date-time ISO 8601 datetime of when the event occurred.

data.event_type

enum: fax.media.processed The type of event being delivered.

data.payload.connection_id

string The ID of the connection used to send the fax.

data.payload.direction

enum: inbound, outbound The direction of the fax.

data.payload.fax_id

uuid Identifies the fax.

data.payload.original_media_url

string The original URL to the PDF used for the fax's media.

data.payload.media_name

string The media_name used for the fax's media.

data.payload.to

string The phone number, in E.164 format, the fax will be sent to or SIP URI

data.payload.from

string The phone number, in E.164 format, the fax will be sent from.

data.payload.user_id

uuid Identifier of the user to whom the fax belongs

data.payload.status

enum: media.processed The status of the fax.

data.payload.client_state

string State received from a command.

meta.attempt

integer The delivery attempt number.

meta.delivered_to

uri The URL the webhook was delivered to.

fax.queued

Field Type Description

data.record_type

enum: event Identifies the type of the resource.

data.id

uuid Identifies the type of resource.

data.occurred_at

date-time ISO 8601 datetime of when the event occurred.

data.event_type

enum: fax.queued The type of event being delivered.

data.payload.connection_id

string The ID of the connection used to send the fax.

data.payload.direction

enum: inbound, outbound The direction of the fax.

data.payload.fax_id

uuid Identifies the fax.

data.payload.original_media_url

string The original URL to the PDF used for the fax's media.

data.payload.media_name

string The media_name used for the fax's media.

data.payload.to

string The phone number, in E.164 format, the fax will be sent to or SIP URI

data.payload.from

string The phone number, in E.164 format, the fax will be sent from.

data.payload.user_id

uuid Identifier of the user to whom the fax belongs

data.payload.status

enum: queued The status of the fax.

data.payload.client_state

string State received from a command.

meta.attempt

integer The delivery attempt number.

meta.delivered_to

uri The URL the webhook was delivered to.

fax.sending.started

Field Type Description

data.record_type

enum: event Identifies the type of the resource.

data.id

uuid Identifies the type of resource.

data.occurred_at

date-time ISO 8601 datetime of when the event occurred.

data.event_type

enum: fax.sending.started The type of event being delivered.

data.payload.connection_id

string The ID of the connection used to send the fax.

data.payload.direction

enum: inbound, outbound The direction of the fax.

data.payload.fax_id

uuid Identifies the fax.

data.payload.original_media_url

string The original URL to the PDF used for the fax's media.

data.payload.media_name

string The media_name used for the fax's media.

data.payload.to

string The phone number, in E.164 format, the fax will be sent to or SIP URI

data.payload.from

string The phone number, in E.164 format, the fax will be sent from.

data.payload.user_id

uuid Identifier of the user to whom the fax belongs

data.payload.status

enum: sending The status of the fax.

data.payload.client_state

string State received from a command.

meta.attempt

integer The delivery attempt number.

meta.delivered_to

uri The URL the webhook was delivered to.

telnyx-fax-python

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In your webhook handler (e.g., Flask — use raw body, not parsed JSON):

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