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How HMRC cut costs by modernising and migrating 450+ APIs
The team adopted a ‘lift and shift’ migration to Kubernetes which eliminated technical debt and was completed without any service interruption.
HMRC needed to complete a critical migration of its legacy Integration Framework (IF) platform to a more modern and secure environment, to enable effective, secure data exchange between multiple IT systems. The legacy platform relied on RHEL-7 and Docker Swarm which were both approaching the end of their support lifecycle, posing significant security and stability risks.
Equal Experts helped HMRC to complete the migration using a simultaneous “build-test-migrate” delivery mechanism, moving more than 450 APIs to the strategic HIP solution. By utilising a weighted traffic policy and a focused proof of concept, the team successfully migrated services handling millions of daily requests in just 15 months. The project not only modernised the tech stack to RHEL-8 and Kubernetes but also maintained a 100% uptime record for API consumers.
Outcomes
Zero
service interruptions for API consumers during the 15-month migration
450+ APIs
successfully migrated, supporting millions of daily requests
Delivered six-figure savings
by retiring legacy infrastructure and optimising platform efficiency
About HMRC
HMRC (His Majesty’s Revenue and Customs) is the UK’s tax, payments, and customs authority. It collects the money that pays for the UK’s public services and helps families and individuals with targeted financial support.
Industry
Government & Public Sector
Organisation size
Government Department
Location
UK
Project length
15 months, ongoing
Challenge
Securing critical infrastructure against unsupported legacy technology
The original IF platform was built on RHEL-7 and Docker Swarm, technologies that were reaching the end of their support lifecycle. This meant that the platform would no longer receive critical security updates or bug fixes, creating a significant risk for the high-priority services HMRC hosts.
The challenge was to migrate these essential APIs to a modern, strategic solution (HIP) without disrupting service for millions of daily users.
Solution
A phased "build-test-migrate" approach using Kubernetes
Equal Experts implemented a ‘lift and shift’ strategy, focusing on RHEL-8 and Kubernetes to enable auto-scaling and self-healing. The project began with a proof of concept to demonstrate that traffic could be redirected at an individual API level using a weighted policy, such as sending 10% of traffic to the new HIP IF and 90% to the original.
The team split the build into three distinct phases: internal sync APIs, external APIs and Async APIs. This allowed migration to begin on internal traffic while the build for external components was still underway. This simultaneous delivery mechanism ensured that the project moved at pace while maintaining a rollback process to toggle traffic back if any issues were identified.
Results
Improved resilience, reduced costs, and seamless scalability
In addition to the successful migration of 450+ APIs, the project delivered significant operational benefits. The move to Kubernetes introduced self-healing and auto-scaling, which the Live Services team reported had improved the performance of dynamic loads.
Despite the introduction of two new APIs that tripled the traffic volume during the project, the flexible migration plan absorbed the increase without impacting delivery timelines. Finally, the migration cleared historical technical debt and aligns with the Chief Engineering Platform Office strategy for cost optimisation, resulting in significant annual AWS savings.