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Choose your sector identifier

The sector identifier is a uniform resource identifier (URI) which GOV.UK One Login uses to create a pairwise user identifier, called the ‘subject identifier’.

This means you can use the sector identifier to:

  • share users across multiple services
  • explicitly prevent services from sharing users

You must set the sector identifier when you register your service with GOV.UK One Login.

Warning Do not change the sector identifier once your service has started to sign up or migrate users. It will change the subject identifiers GOV.UK One Login creates for each individual user.

If you’re not sure whether you want to share users across services when onboarding your first service, you should use a generic sector identifier. Once your second service onboards, you must decide whether your services will share users.

Set your sector identifier

Make sure your sector identifier:

  • accurately represents your service or services which share users
  • does not contain path information

For example, you should use https://do-a-thing.service.gov.uk not https://service.gov.uk/do-a-thing. GOV.UK One Login only uses the host part of the URI.

The following table shows an example of how to set your sector identifier using the (fictional) Department of Mythical Creatures, which has 3 services:

  • tax your dragon
  • register your hydra
  • report a unicorn
User sharing How to set your sector identifier   Example          
Share users across all services Set the sector identifier in all services to the same value. Set https://mythical-creatures.gov.uk as the sector_identifier_uri for all 3 services.
Prevent services from sharing users Set the sector identifier in each service to a different value. Set a separate sector_identifier_uri for each service:
  • http://register-your-hydra.mythical-creatures.gov.uk

  • http://tax-your-dragon.mythical-creatures.gov.uk

  • http://report-a-unicorn.mythical-creatures.gov.uk
Share users across some services Set the sector identifier in the services that share users to the same value.

Give the services that should not share users a different sector identifier.		 Set https://mythical-creatures.gov.uk as the sector_identifier_uri for ‘register your hydra’ and ‘report a unicorn’ to share users.

Set https://tax-your-dragon.mythical-creatures.gov.uk as the sector_identifier_uri for ‘tax your dragon’ to have a separate user base.
This page was last reviewed on 9 February 2024.