Preparing a product and team for the next stage of growth

As TaxZap grew, we stepped in to stabilise the platform, fix recurring bugs, and adapt the data gathering system while the company built its engineering team.

Background

TaxZap is a fintech platform that simplifies tax returns in Ireland and the UK, helping users identify expenses and deductions they can claim from HMRC or Revenue.

When we joined, the product was already live with real users, but some core data was still stored in Google Sheets—a solution that worked for early testing but couldn't scale. The company had recently lost their developer and was struggling to hire a senior technical leader.

What we did

We stepped in to provide technical leadership and development support during this transition, focusing on strengthening the app's infrastructure and moving beyond its early limitations.

Key contributions included:

• migrating core data systems from Google Sheets to a proper custom database
• helping to build a more robust backend
• advising the founders on technical decisions and roadmap priorities
• mentoring and managing the first junior engineer they hired

We helped the junior developer understand the codebase, gave them increasing autonomy, and introduced basic engineering processes like daily stand-ups and backlog management to structure the growing team.

As the company expanded and hired a CTO, our involvement then naturally decreased.

Results & reflections

Our work helped TaxZap scale across multiple markets by strengthening infrastructure, migrating critical systems from spreadsheets to a proper database, and establishing engineering processes for team growth.

Since we joined, TaxZap expanded from Ireland to the UK and has helped over 100,000 customers get back €10 million in tax returns.

The project demonstrated how interim technical leadership can build and train a new engineering team capable of operating independently after the project ends.