Test your integration

Use GOV.UK Pay testing features to check your integration before you go live, and to test changes after your service is live.

The way you test depends on:

whether your service is live
which payment service provider (PSP) you use
whether you are testing the GOV.UK Pay API, the full user journey, or both

Choose a testing mode

Each GOV.UK Pay service has one test point.

You can use it in 2 modes:

‘not live yet’ for a new service
sandbox for a live service

Use ‘not live yet’ for a new service

When you first create a GOV.UK Pay service, it is labelled ‘not live yet’ in the GOV.UK Pay admin tool.

Use this mode to:

explore how the GOV.UK Pay API works
test payments
test service settings
check your integration before you go live

Use sandbox for a live service

After your service goes live, use sandbox mode to test changes.

To enter sandbox mode:

From the admin tool dashboard, select Enter sandbox mode.
On the Enter sandbox mode page, select Enter sandbox mode.

You can use sandbox mode to:

make test payments
view test transactions
try different settings and functionality
run automated smoke tests

Changes in sandbox mode do not affect your live service. Users can still make payments to the live version.

You can leave sandbox mode at any time.

Important limitations when testing GOV.UK Pay

Do not use both testing modes for automated integration tests that run when you change your code.

If you need automated integration tests, build a stub to simulate the GOV.UK Pay API instead. For example, you can use WireMock.

In sandbox mode, use the same test API keys created in ‘not live yet’ mode. Create new live API keys only when you go live to take payments.

What you can test by payment service provider

If your PSP is Stripe

If your service uses Stripe, you can use ‘not live yet’ and sandbox modes to test:

transaction fees
payments to your bank account
3D Secure (3DS) with specific test card numbers

If your PSP is Worldpay

If your service uses Worldpay, you can use ‘not live yet’ and sandbox modes for:

reporting on payments
smoke testing
viewing transactions
refunding transactions

Worldpay does not support 3DS testing in sandbox mode.

Worldpay test accounts

You can link a Worldpay test account to GOV.UK Pay.

Some services use a Worldpay test account to connect GOV.UK Pay to Worldpay reporting products.

Most organisations do not need a Worldpay test account. We do not recommend using one unless you have a clear reason.

If you use a Worldpay test account:

GOV.UK Pay cannot support problems with the account
you should not use it for long-term automated testing

To ask for a Worldpay test account, email govuk-pay-support@digital.cabinet-office.gov.uk.

If we approve your request, we will add the test account as a separate GOV.UK Pay service.

Test the whole user journey

Test the full user journey as well as the API.

You can create a reusable link in the GOV.UK Pay admin tool. It behaves like a payment link created through the API.

You can use the link to:

open a GOV.UK Pay payment page from your prototype
complete a test payment
send the user back to your service with a return_url
test the full payment journey

To create a reusable payment link:

Sign in to the the GOV.UK Pay admin tool.
Select the service you want to test in My services.
Select Test with your users to create the link.

You can also:

use mock card numbers to test successful and unsuccessful payments
use HTTP instead of HTTPS for the return_url while your service is in sandbox or ‘not live yet’ mode
test any payment links you have already set up

You do not need to set up a secure URL for testing.

Performance testing

You must contact us to get written approval before you do any performance testing.

Use mock card numbers

Use mock card numbers when you test payments. Do not use real card numbers.

You can use any valid value for the other payment fields. For example, the card expiry date can be any future date.

Mock card numbers work for all test payments in sandbox and ‘not live yet’ modes.

There are separate sets of mock card numbers for:

Stripe services
Worldpay services

Mock card numbers for Stripe

The PSP transaction fee depends on the card country.

Testing action	Card number	Card brand	Card type	Country
Successful payment	4000008260000000	Visa	Credit	UK
Successful payment	4000058260000005	Visa	Debit	UK
Successful payment	4000002500000003	Visa	Credit	France
Successful payment	4242424242424242	Visa	Credit	US
Successful payment	4000056655665556	Visa	Debit	US
Successful payment	5105105105105100	Mastercard	Debit	US
Successful payment	5200828282828210	Mastercard	Debit	US
Successful payment	371449635398431	American Express	Credit	US
Requires 3DS check	4000002500003155	Visa	Credit	France
Card declined	4000000000000002	Visa	Credit or debit	US
Card expired	4000000000000069	Visa	Credit or debit	US
Invalid CVC code	4000000000000127	Visa	Credit or debit	US
Payment disputed and lost	4000000000000259	Visa	Credit	US
Payment disputed and won	4000000000002685	Visa	Credit	US
General error	4000000000000119	Visa	Credit or debit	US

Test recurring payments for a Stripe service

There are additional mock card numbers to test recurring payments with Stripe.

Use these mock card numbers to test recurring payments with Stripe.

Recurring payments have 2 steps:

Take an initial payment to set up an agreement.
Take later recurring payments automatically.

Each test card gives a result for both steps.

Testing actions	Card number	Card brand	Card type	Country
Successful set up payment without 3DS Successful recurring payments	4242424242424242	Visa	Credit	US
Successful set up payment with 3DS Successful recurring payments	4000002500003155	Visa	Credit	France
Successful set up payment with 3DS Unsuccessful recurring payments	4000002760003184	Visa	Credit	Germany
Unsuccessful set up payment	4000000000009995	Visa	Credit	US

Mock card numbers for Worldpay

Testing action	Card number	Card brand	Card type
Successful payment	4444333322221111	Visa	Credit
Successful payment	4242424242424242	Visa	Credit
Successful payment	4000056655665556	Visa	Debit
Successful payment	4988080000000000	Visa	Debit - corporate
Successful payment	4000160000000004	Visa	Debit - prepaid
Successful payment	4131840000000003	Visa	Debit - corporate prepaid
Successful payment	4111111111111111	Visa	Credit - corporate
Successful payment	4000000000000010	Visa	Credit or debit
Successful payment	222100000000000	Mastercard	Credit
Successful payment	5105105105105100	Mastercard	Debit
Successful payment	5200828282828210	Mastercard	Debit
Successful payment	371449635398431	American Express	Credit
Successful payment	3566002020360505	JCB	Credit
Successful payment	6011000990139424	Discover	Credit
Card type not accepted	6759649826438453	Maestro	Debit
Card declined	4000000000000002	Visa	Credit or debit
Card expired	4000000000000069	Visa	Credit or debit
Invalid CVC code	4000000000000127	Visa	Credit or debit
General error	4000000000000119	Visa	Credit or debit

Test recurring payments for a Worldpay service

Use these mock card numbers to test recurring payments with Worldpay.

Recurring payments have 2 steps:

Take an initial payment to set up an agreement.
Take later recurring payments automatically.

Each test card gives a result for both steps.

Testing actions	Card number	Card brand	Card type
1. Successful set up payment 2. Successful recurring payment	4000056655665556	Visa	Debit
1. Successful set up payment 2. Unsuccessful recurring payment	5105105105105100	Mastercard	Debit

Use mock email addresses

If you are testing manually, you can use real email addresses.

If you are doing automated tests, you must use one of these mock email addresses.

simulate-delivered@notifications.service.gov.uk
simulate-delivered-2@notifications.service.gov.uk
simulate-delivered-3@notifications.service.gov.uk