Hello Alberto,

We're writing to inform you that DeepL plans to deprecate two rarely-used API features.

The changes will go into effect on or after March 14, 2025. If you use either feature, you will need to update your application before this date to continue using the DeepL API. 

You will no longer be able to send GET requests or query parameters to the /translate endpoint. Going forward, /translate will accept only POST requests with data included in the request body.

You will no longer be able to authenticate a request to any endpoint by sending an API key in a query parameter. Instead, send your API key in an HTTP header named Authorization.

Use POST for /translate

Going forward, you will need to send requests to the /translate endpoint using POST, not GET. This also means you will not be able to send such requests using only a URL. You will need to send data in the request body, not in query parameters.

Going forward, the /translate endpoint will reject any GET request. Similarly, it will reject a request made with a URL and query string, like this:

Authenticate with an HTTP header

Going forward, you will need to authorize any API request, to any endpoint, by including your API key in an HTTP header named Authorization, like this:

Authorization: DeepL-Auth-Key [yourAuthKey]

Going forward, you will not be able to authorize any request, to any endpoint, by including your API key in an auth_key query parameter.

For more information, please see this detailed announcement.

We apologize for any inconvenience these changes might cause. If you have any questions, or you are concerned with our planned timeline, please contact your DeepL representative or our support team. We will do our very best to support you in advance of these changes.

Kind regards, 

The DeepL Team