Senior Modelling Engineer I

• Join Runna’s Train Team as a Senior Modelling Engineer, working hybrid from London 3 days a week. • Work at the heart of Runna’s mission: delivering the best possible training to hundreds of thousands of runners. • Build personalised training plans that adapt dynamically at scale. • Analyse performance data to recommend training adjustments and give users insight. • Collaborate with coaches to bring their expertise to users through algorithms. • Join a cross-functional team of 35+ across engineering, product, design and coaching.

• Bring around 3+ years of experience in a software engineering or modelling-focused role. • Write production-quality, object-oriented Python code. • Design and implement complex algorithms and modelling components such as exercise scheduling. • Apply quantitative methods gained through study or practical experience in a field like Computer Science, Maths, Physics or Engineering. • Test modelling-focused software to ensure quality and maintainability. • Model best practice and help raise the quality and pace of the team. • Communicate and collaborate well with a pragmatic, detail-oriented mindset. • Enjoy continuous deployment, test automation, pair programming and shared code ownership.

• Bring experience with deployment, release cycles or CI/CD. • Show experience delivering features end to end, from design through release and support. • Bring experience in a product-focused organisation building consumer apps. • Show experience with large Python projects and scalable design patterns.

• Build, test and deliver training features such as adjusting plans for illness, injury and weather. • Add new goal types, such as training for consistency. • Experiment with new algorithms, design patterns, optimisations and modelling approaches. • Coach engineers through guidance, mentorship and code reviews without creating bottlenecks. • Work with coaches to deliver their expertise to users. • Use data to influence training algorithms where possible. • Design and implement tests that keep training consistent and accurate.

Runna is one of the most exciting fitness startups in the UK right now, and the Strava acquisition only makes the opportunity bigger. In under four years from launch, Dom and Ben built Runna from a website selling personalised PDF training plans to a globally rated running coaching app, a finalist for Apple's iPhone App of the Year, and ultimately an acquisition by the world's largest fitness community. The team has grown to over 150 people across London and Boston, and Strava has publicly committed to investing further in growing both the team and the product. What stands out on Glassdoor (4.9/5 from 31 reviews, with 100% of employees recommending it) is how consistently people praise the culture, the kindness of their colleagues, and the quality of the leadership. Benefits are genuinely strong for a company this size: private health insurance, enhanced parental leave (up to 20 weeks fully paid), Strava equity, a smartwatch as you pass probation, 25 days holiday plus bank holidays, and a paid hour each week to go for a run during work hours. They operate a flexi-hybrid model, typically three days a week in their Vauxhall office. The team runs bi-weekly together, and Workout Wednesdays include exercise plus a free lunch. The main thing to be aware of is that this is a fast-paced startup environment where priorities can shift quickly, which some reviewers flag as a challenge. There is also a slight bias toward hiring passionate runners, though this has been improving. If you want to work on a product that helped millions of runners train, alongside kind and ambitious people, with the backing and scale of Strava behind you, Runna is a brilliant opportunity.

• Earn £70,000–£78,000 plus Strava stock through long-term incentive programmes. • Work flexibly, typically 3 days a week in the Vauxhall office. • Take 25 days’ holiday plus bank holidays. • Get free Runna and Strava subscriptions for you and 3 friends. • Receive a yearly allowance for gear, events and the gym, plus a Headspace membership. • Get Bupa private health insurance, a workplace pension and Modern Health mental wellness support. • Access Carrot fertility, hormonal health and family-forming support.

Runna is a running training app that gives everyday runners world-class training plans, coaching and community, from improving a 5k time to finishing a first marathon. It was named one of Apple’s three global finalists for iPhone App of the Year in 2024 and was acquired by Strava in 2025. Runna aims to become the leading global training platform for millions of runners.