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Header Fields

Developers Integration Dictionary

During the process of creating your integration you will bump into these words and functions.


Authorization is made by including the header Authorization in the API request. The value should be “Bearer” and an active Access-Token for the user.

Type of content

Fortnox API supports both JSON and XML. You will need to use the header fields Content-Type and Accept to specify which type you use.

The value for these header fields should be either application/json or application/xml depending on which you use.

For requests where the content is a file, like in archive or inbox, a special content-type is used, this type is multipart/form-data. The header field “accept” should still be either JSON or XML, this specifies in which format you want the return data to be in.


This is an example of how the header should look with all the header fields filled in correctly.

Accept: application/xml
Authorization: Bearer {Access-Token}
Content-Type: application/xml
Accept: application/json
Authorization: Bearer {Access-Token}
Content-Type: application/json