Part of Integration process overview
Stage 2 - Build
Find out how to gain access to our test environment in order to start development with the NHS e-Referral Service API.
- Create and register your application
- Get access to our test environment
- Provision test data
- Configure e-RS
- Request the Supplier Conformance Assessment List (SCAL)
- Build your software
2.1 Create and register your application
You will need to create an application and register it in the integration test (INT) environment as per the below steps. You will need the information produced to complete the form at 2.21 Integration testing.
2.2 Get access to our test environment
You may already have had experience of our sandbox environment.
This step will provide you with access to the INT environment. It provides a more realistic setting for testing than is possible in a sandbox, including authorisation, release and assurance testing.
2.21 Integration testing
The integration environment should be used to test and assure your software in an integrated manner.
This environment is:
- where the majority of your integration efforts will take place
- where we conduct witness testing for your application
- stateful, so data will be persisted
- representative of the production estate
To get access, please complete the integration test environment form. You will need:
- the use case information that you reviewed at 1.2 Validate your use case
- the application information produced at 2.1 Create and register your application
- to let us know if you plan to use your own Patient Administration System (PAS) or the NHSE test PAS
We will review your form and give feedback if needed.
After addressing any feedback, we will set you up in the integration environment and notify you by email. You’ll also receive a test data pack, which you’ll need for step 2.3 Provision test data. This process may take up to 10 working days.
2.22 Performance testing
We do not provide an environment for performance testing, in line with other NHS APIs. The INT environment has low rate limits to protect them against overuse.
If you need to performance test your integration, we recommend you build stubs to simulate our API.
The data in our test environment is not representative nor at the same scale as production. Do not undertake performance testing against this environment.
2.3 Provision test data
Use the test data we have provided you with at 2.21 Integration testing to test your software in our integration environment.
The test data includes:
- patients
- GP surgery
- NHS trust organisation
- NHS trust site
The test data provided here is required to set up test referrals as outlined in section 2.4 Configure e-RS.
2.4 Configure e-RS
In this step, you will be required to familiarise yourself with the e-RS application.
Whether you are integrating as a referrer or a provider, you will have to play both roles to configure and set up test referral data in e-RS.
Additional guidance and implementation resources can be found in our document library.
2.41 Set up test services
To start creating referrals you will first require test services in the e-RS web-based application.
You can access the e-RS application using this URL: https://int-ers.nhs.uk. You will need to log-in with an INT smartcard, security key or another supported authenticator option.
Follow this detailed guide for creating services in the INT environment.
2.42 Test PAS
If you are intending to use directly bookable services, you will require a PAS to supply appointment slots to e-RS. The ITOC team can create these for you with a test PAS, if you do not have your own. You will have indicated your requirement for a test PAS on the form you completed at 2.21 Integration testing.
Once you have set up your test services, please email the ITOC team ([email protected]) and provide them with your test service IDs so they can create slots against them for you.
Please note that beyond creating appointment slots, we do not offer any support for PAS issues or config changes. Use of the test PAS is at your own risk. NHS England will not accept responsibility for missed test schedules.
2.43 Set up referrals
You will need to create test referrals in order to carry out your tests.
We recommend starting section 2.5 Request the Supplier Conformance Assessment List (SCAL), while completing this stage.
2.5 Request the Supplier Conformance Assessment List (SCAL)
2.51 What is the SCAL?
The SCAL is a document that asks for information about your product. It helps ensure your software is safe, secure and meets information governance and clinical standards.
It is an Excel spreadsheet with several tabs.
Each SCAL is unique to:
- your product
- the NHS service you are integrating with
Many sections of the SCAL can be completed in parallel to your testing.
We recommended that you familiarise yourself with the SCAL as early in the process as possible. You can access the latest SCAL as part of the design stage.
During assurance, we may ask you to complete the uplifted version of the SCAL, if we introduce updates or new requirements. You can access the SCAL change log.
2.52 Request and review the SCAL
The SCAL document is tailored to your integrated software if:
- your product uses several NHS England APIs or services - you’ll have a single SCAL that covers them all
- you have more than one product - you need a separate SCAL for each product
To get an appropriate SCAL template for your product, request the SCAL from the e-RS Solution Assurance team at [email protected].
The e-RS Solution Assurance team will either create a new SCAL template for you, or find your existing SCAL, and add the latest version of the e-RS requirements tabs on to your existing SCAL.
Please review and complete the SCAL and send an email to [email protected] indicating when you expect to be ready for witness testing.
2.6 Build your software
You now have everything you need to start building your software. Complete module, system, and integration testing, then progress into the assurance stage.
Contact us
Get support on integrating with our API by checking out our developer community.
You can:
- search and find answers to your query
- post your own questions
- join a community of professionals with similar objectives
Last edited: 21 August 2025 11:32 am