At the heart of IR’s business transformation is the replacement of the legacy tax system with a new custom-off-the-shelf solution. IR shares information from this core tax system with other government agencies, software providers, partners and suppliers, which integrate with its systems for the delivery of IR services countrywide. In an increasingly common IT challenge, the systems are being upgraded without interruption to services provided – the equivalent of changing engines on an aeroplane whilst in flight.

IR’s Director of Digital Change Rogan Clarke describes the business transformation as one of the most ambitious he’s ever seen. “IR got into the transformation programme because legacy systems limited our ability to adapt to new policy. At the heart of it, it was decided that if we’re going to change, let’s think big – and IR really did think big. Exceptionally big.”

IR Business Transformation Testing Lead Chris Hourigan points out two essential factors relating to the organisation’s systems: “We operate complex systems engaging with hundreds of thousands of customers across multiple channels. At the same time, the requirement for accuracy is high, so we must execute assurance practices which maintain a level of integrity and consistency for all channels and customers.”

The initial and obvious benefit was acceleration. We are able to onboard new parties rapidly by enabling them to self-service with testing, reducing their need for physical engagement with IR. Provided with the right information, it makes testing easier for them and for us, so both parties win"

Chris Hourigan, Business Transformation Testing Lead, Inland Revenue


Assurity initially set out to test the ‘digital border’ between IR and its partners. This allowed for easier integration by bypassing structures which interfere with testing, such as firewalls, network, and hardware configurations. The exercise gave way to the creation of cloud-hosted test assets accessible by partners which would allow them to emulate live interactions and evaluate the results.

The resulting Digital Partner Services (DPS) platform – approved to meet government standards for security – extends self-service automated testing for partners, equipping them to understand, code and test their integrations against IR APIs, independent of and decoupled from IR infrastructure. Provided as a pay-as-you-go service, the solution is made available to IR partners as required.

An initial trial validated the DPS concept by providing emulated digital border testing services to a United Kingdom-based partner. With no engagement with IR, this partner consumed the test assets as a service to conduct hundreds of tests in a day – a considerable result which replaced the previous two to four weeks engagement for integration assurance.

In due course, additional functional and smoke service tests were employed through all environments to ensure an automated regression ran daily, capturing change impacts at source. Promoting asset reuse, the emulated service tests are employed by partner performance test teams to evaluate IR’s exposed APIs.

Following the DevOps ethos, the DPS service tests are employed to validate the production implementation, allowing IR for the first time to introduce new services tested against IR endpoints, without depending on an external party. Subsequently, the service journey tests were employed as an enduring Customer Experience Monitor (CEM) service in the production environment, providing real-time feedback on service performance.


The successful delivery of the business transformation project depends on a high degree of assurance that every new service, every customer interaction and every system underpinning delivery across multiple channels works – not only the first time a customer engages with IR, but every time. With DPS, this goal is accelerated, with shortened development cycles and time to market. Third parties are equipped to build and test their systems in parallel with IR and can conduct their assurance programmes simultaneously and independently of the revenue authority’s teams.

Already, multiple parallel parties have tested their systems at the same time, far superseding the previously necessary ‘one-on-one’ approach. DPS provides economies of scale and scope, while positioning testing where the partner is. Self-service integration testing makes this crucial process easy for IR partners – and easy for IR itself. There’s hard data to support claims of efficiency gains. Firewall changes have shifted from days to minutes to enable customers to engage in testing. Third-party integrations are up to four times faster. And the time taken for integration testing is reduced from weeks to days.

The deployment of new tax products is inevitably accompanied by a high volume of change internal to IR; with DPS, continuous testing captures issues that would impact external systems, de-risking the interdependent systems of partners by eliminating issues before they reach production.