Document Authentication Integration

Integration guide

This page provides a step-by-step guide on how to integrate Document Authentication.


Check what you need to have in place before you begin your integration:


  • You need your Fourthline API key.
  • The client must have previously been onboarded by Fourthline or another licensed KYC provider.


Set up handling for the Document Authentication statuses.


Set up a webhook and handling for the Document Authentication notifications.


Discuss with your implementation manager the following configuration options:

NFC authenticationNFC authentication included or not
Required dataWhich data points in Create Document Authentication > clientData you require

Document photo requirements

The expected ID documents in differ per country.

For every required document side, you must provide a flat image and a tilted image to help us detect more security features.

For clients previously onboarded by:

  • Fourthline: These values are retrieved automatically from the client's latest successful Identity Verification case.
  • Another KYC provider: You are responsible for the quality and accuracy of the data.

See the following table for the expected number of files per document type:

Document typeDocument sidePhoto angle
Passport2 x front1 x flat
1 x tilted
National ID Card2 x front
2 x back
1 x flat
1 x tilted
Paper ID2 x inside right
1 x inside left
1 x back
1 x flat
1 x tilted
* Only for inside right
Driving license2 x front
2 x back
1 x flat
1 x tilted
Residence permit2 x front
2 x back
1 x flat
1 x tilted
Document video
Video length <10 seconds
• For App Drop-in and API-only integration: mp4 format
• For Web SDK integration: webm format
1 x frontN/A


Fourthline's platform is built to detect authentic ID documents with correctly matching personal data.
This means, by the nature of our business, we can't provide dummy documents, photos, files, or data for testing.

To test your Document Authentication solution:

  1. Use official specimen documents, or the real ID documents and data of your colleagues, to create test cases in the sandbox environment.

  2. To safeguard the privacy of your colleagues and their data, when you have finished testing, contact your implementation manager to delete all testing data from the sandbox.

More information
For more information about how Fourthline protects data, see Security & Compliance.

Top of page