Web SDK Setup

Integrations guide

This page sets out step-by-step instructions for setting up the Web SDK.

SDK configuration

Provide your implementation manager with the following configuration specifications:

Required URLsFor the redirect flow hosted by you, provide the URL for both sandbox and production.
For the product workflow hosted by Fourthline, provide for both sandbox and production one of the following:
• Custom domain
• Custom Fourthline domain
Redirect optionSpecify which redirect option you want to use:
• QR code
For SMS redirect:
• Specify the languages you want to support.
• Specify a default language.
• Provide the SMS message copy per language.
• Provide the SMS originator (indicates to the client who the SMS is from) as a string of 3–11 characters.
UI customizationProvide the styles file to customize the UI and your logo.

Required URLs

The redirect flow is typically embedded in your website and hosted by you, so you must provide us the URL for both sandbox and production, e.g. www.mysite.com.

The product flow is hosted by Fourthline and can be served using either:

Custom domainProvide URL, e.g.:
Provide URL, e.g.:
Custom Fourthline domainhttps://{yourstring}.app.sandbox.fourthline.comhttps://{yourstring}.app.fourthline.com

If you opt for a custom domain, you are responsible for the DNS configuration.

Redirect options

Specify which redirect option you want to use: QR code and/or SMS.

For SMS redirect:

  • Specify the languages you want to support.
  • Specify a default language.
  • Provide the SMS message copy per language.
  • Provide the SMS originator (indicates to the client who the SMS is from) as a string of 3-11 characters.

User guide

Before you get started, check the following user information:

Setup methods

You can set up your Web SDK via either embedding or WebView integration for mobile apps.

For a better mobile experience and NFC support than WebView integration, we recommend integrating with our App Drop-in.

Supported browsers

The web is a moving target. Every browser has a potentially different implementation or set of features or APIs it exposes. We require browsers to expose specific web APIs and support browsers at the pace that vendors implement them.

We require the following web APIs:

APIMethodGlobal coverageMozilla developer documentation
DeviceMotionEventacceleration62.08%acceleration property (experimental)
GeolocationgetCurrentPosition96.14%getCurrentPosition() method
MediaDevicesgetUserMedia92.71%getUserMedia() method
MediaRecorderisTypeSupported89.87%isTypeSupported() static method
MediaRecorderstart89.87%start() method
MediaRecorderstop89.84%stop() method
MediaRecorderondataavailable89.84%dataavailable event
Navigatorlanguage96.17%language property
NavigatorsessionStorage96.18%sessionStorage property
NavigatoruserAgent96.33%userAgent property
Navigatorvibrate75.03%vibrate() method
Permissionsquery75.13%query() method (experimental)

For security and performance reasons, we recommend using an up-to-date modern browser and updating the device to the latest version supported by the vendor.

Unsupported browsers

If a client tries to use a browser that doesn't support the required APIs, they receive an Unsupported browser error.
The validation code in the URL is not consumed at this point, so the client can try a different browser without having to restart the redirect flow.

Unsupported browser error

Unsupported browser error

Supported devices

We support tablets on a best-effort basis only.

We check the browser settings on the tablet and start the flow. If the flow can't be completed on that tablet model, the client needs to try from a mobile phone or another device.

Supported languages

Supported languages and formality:

Dutchnlformal, informal
English (default)eninformal

Case zipfile

You can download an XML file containing all of the data collected by the SDK via a Get case zipfile request.

The zipfile also contains all identification files (i.e. ID document and selfie photos and videos) collected by the SDK if you want to review them.

Overlay permissions

If other apps are overlaying the client's screen, they may get the following error:

This site can’t ask for your permission. Close any bubbles or overlays from other apps. Then try again.

The client needs to deactivate overlay permissions of other apps in their device settings.

Try sharing the following guidance: How to Geek – How to Fix the Screen Overlay Detected Error on Android


If you have a Fourthline Dashboard, you can test the flow using the TestMe functionality.

You can use any supported ID document type with dummy data.

For support or any questions, contact your implementation manager.

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