concurrent users supported at desktop-class responsiveness
revenue potential unlocked through new client onboarding
interruption to feature delivery throughout the programme
About the company
Alphatax, formerly known as Tax Systems, is the leading provider of tax compliance software in the UK and Ireland, trusted by over 1,500 clients, including 40% of the FTSE 100 and 80% of the top accountancy firms. Its flagship corporate tax product codifies more than 100,000 tax rules and underpins critical tax reporting workflows for organisations ranging from FTSE 250 corporations to global firms.
Backed by private equity, the business has been on a sustained growth trajectory: Bowmark Capital took the company private in 2019 and, under its ownership, Alphatax doubled its revenue and profit. Since then, Bowmark sold the business to Providence Equity Partners in a successful exit, with Providence's investment now backing the company's continued international expansion under its new Alphatax brand.
The Challenge
The challenge
Central to that growth story was Alphatax's transition from an industry-leading desktop application to a modern, cloud-native SaaS platform. The ambition was significant: a product capable of serving enterprise clients, supporting a growing customer base, and meeting the expectations of both customers and investors.
As the platform matured and customer adoption accelerated, the engineering challenge shifted: the web application needed to support far greater concurrent usage while matching the speed and responsiveness of the highly optimised desktop product it was replacing. Delivering that at pace, without interrupting feature development at a critical point in the business's growth, called for specialist expertise. Alphatax invited Codurance to partner on the programme.
The Project
What we delivered
Codurance worked in close, embedded collaboration with the Alphatax engineering team across an 18-month partnership spanning performance engineering, platform scalability, and long-term engineering capability.
Performance and scalability
Codurance deployed a comprehensive observability and monitoring layer around the platform's core calculation engine, enabling the team to test hypotheses about where performance constraints sat and why. Improvements were sequenced incrementally alongside the existing roadmap, so commercial and product priorities were never compromised.
Engineering capability for the long term
With the platform performing at scale, Codurance shifted into a coaching and enablement capacity, embedding practices such as test-driven development, Continuous Integration discipline, and structured code review directly within Alphatax's squads. A DORA metrics framework was implemented and surfaced through Azure Fabric, giving leadership an evidence-based view of engineering performance, while developer experience improvements reduced friction and shortened feedback loops.
- Observability platform deployed around the core calculation engine
- Platform scaled to 1,000+ concurrent users across nine user journeys, matching desktop-class responsiveness
- Performance testing embedded into the SDLC to prevent regression
- Engineering coaching delivered through embedded, practitioner-led collaboration
- DORA metrics framework implemented and adopted by leadership
- Internal teams upskilled to own and extend the platform independently
Neil Robbins
CTO, Alphatax
The Outcome
Outcomes
The partnership gave Alphatax an enterprise-ready platform precisely as the business needed to demonstrate scale, resilience, and growth potential to the market. Within months, concurrency and responsiveness targets were met; the platform went on to enable the support of over 1,000 concurrent customers across nine user journeys, unlocking tens of millions of pounds in revenue potential through new client onboarding, with zero interruption to feature delivery.
to first concurrency targets met
metrics embedded and live with leadership
user journeys scaled to enterprise-grade performance
This combination of commercial momentum and engineering maturity formed part of the platform story that underpinned Bowmark's successful private equity exit, selling Alphatax (then Tax Systems) to Providence Equity Partners, following a period in which the business doubled its revenue and profit. A scalable, well-instrumented platform, paired with internal teams capable of sustaining it independently, gave Alphatax the technical foundation to support its next phase of growth under new ownership.