# Fax API

This document provides a detailed user guide and reference documentation on the Fax REST API.

If you have questions please contact us via our [support portal](https://tickets.sinch.com/plugins/servlet/desk/portal/31/create/1559) and a team member will be happy to assist.

Note:
You must create an account on our support portal if you do not have one.

## Authentication

For information on how to authenticate API requests we support two methods [Basic](/docs/fax/api-reference/authentication/basic) or [Oauth2](/docs/fax/api-reference/authentication/oauth)

## Global URL

Sinch has a global server that will route your call to the appropriate geography region automatically:


```shell
https://fax.api.sinch.com/
```

or, you can also specify what location you want to call by prefixing the above global URL with one of the region codes in the table below:

| Region | URL |
|  --- | --- |
| US East Coast | use1.fax.api.sinch.com |
| Europe | eu1.fax.api.sinch.com |
| South America | sae1.fax.api.sinch.com |
| South East Asia 1 | apse1.fax.api.sinch.com |
| South East Asia 2 | apse2.fax.api.sinch.com |


## Formats

By default, all API calls return a JSON response unless otherwise specified.

### Date time fields

All date and time fields are in UTC format unless otherwise specified.

## Deletion and data retention

In general we retain fax logs and media for 13 months and you can access that via the API.

## Errors & statuses

Find error codes and explanations [here](/docs/fax/api-reference/fax/error-messages).

## Webhooks

You can configure your service to use webhooks to send a request to you when faxes arrive or complete on your account.