Harry Grumbar

About Me

I'm a software engineer based in London. I have strengths working in agile teams using industry-standard tools and libraries with over 8 years' experience building and delivering software.

I have experience modeling complex domains for backend systems and a focus on testable and predictable code is core to my programming principles. I'm a strong proponent of functional programming in modern scalable applications and believe it results in fewer bugs, easier testing and more comprehensible code.

When building for the front-end I enjoy using React with which I work with almost exclusively in TypeScript. I am a strong believer that a modern type system and compiler brings many benefits to the reliability of one's code and helps and greatly reduces the number of errors.

For the backend I have extensive experience building Node server applications with microservice architectures, although I am a proponent of using monolithic backends when the situation calls for it. For this I've found I can be very productive with Elixir's Phoenix framework.



Co-founder/CTO / October 2021 - Present

Matchhaus is a network for sports teams. It allows players to plan and manage their matches, engage in team ceremonies, and dig into each others stats and performances.

I created Matchhaus as a side project with a friend back in 2019 and have been working on it full time since October 2021. We've managed to accumulate several thousand regular active users, including a number of paid subscribers.


Senior Software Engineer / May 2018 - September 2021

Bulb is a renewable energy provider that heavily relies on its technology to differentiate itself from the competition. Among the first full-time engineers to be hired I've built products serving millions of users as well as helped shaped the engineering culture while the company went though a period of hyper-growth.

A few of the projects and responsibilities I've been involved with:

  • Developed and evolved Bulb's core member-facing account products, with a focus on accessibility, security, and performance.
  • Designed and built a new business-critical payment system (Bulb Pay) to allow members to effortlessly make payments on their accounts.
  • Re-architected and designed new authentication infrastructure to allow members to access their Bulb accounts more easily and securely.
  • Built complex automation to improve revenue collection and keep member account balances healthy. These services involved processing large volumes of data efficiently and reconciling state changes between runs.
  • Been extensively involved in technical hiring and interviewing, and mentoring junior developers.


Software Engineer / May 2016 - May 2018

Working in a diverse team using multiple languages and tools I was mainly responsible for building web user interfaces for the principle products, "Pro" and "Direct", that serve the users of Goodlord, a platform for streamlining the process of letting a property. We worked in small squads following agile principles delivering fast prototypes as well as infrastructure and dev-ops improvements.

  • Built and maintained the core business logic and UI component library for both platforms in React/TypeScript and accompanying living style guide.
  • Made key architecture and library decisions to ensure that developer happiness was kept high and the codebase remains testable and maintainable.
  • Championed the usage of atomic and functional styles to help control the CSS footprint of our applications.
  • Participated in team "guilds" (Functional Programming, Front-End Dev, Testing, Dev-ops) that allowed us to learn alongside our colleagues and further our knowledge in the respective areas.


CFA Society UK

Investment Management Certificate / 2011

University of Bristol

Master of Engineering, Civil Engineering / October 2006 - June 2010

Skills and Interests

I'm a keen sportsman and particularly enjoy cycling, tennis, hockey and football. I love the outdoors; one of my passions is back-country skiing and ski-touring, when travel and conditions allow it!