This documentation is for developers who want to integrate the Catalyst Notify API with a web application or back office system.

Client libraries

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A developer should be able to set up the API client and start sending test messages in around 30 minutes. A full integration can take a few days, depending on the other systems you’re using.

Using the GOV UK API Clients with Catalyst Notify

To use the GOV UK API clients with Catalyst Notify, you'll need to supply the URL of the Catalyst API when instantiating the client.

Here's an example of overriding the API URL in Ruby:

api_key = "test_key-4a2b347d-4ab7-4ff3-87c7-1b9407e75a62-eb1ebb7a"
api_url = ""
client =, api_url)

For more information about setting the API URL for your client of choice, please see our documentation in GitHub.

Integrate directly with the API

If you cannot use the client libraries, you can integrate directly with the API instead.

Read the REST API documentation (this link opens in a new tab).