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Senior/Lead Backend Engineer

Vilnius

We’re very proud of our achievements:

In July 2024, we secured a $200M investment led by General Atlantic to help revolutionise women’s health, and became the first purely digital consumer women’s health app to achieve unicorn status! 🦄

We’ve had 380M+ downloads, have over 70M monthly users, are #1 by installs in the iOS Health category, hit 4.9 stars on the App Store (3M+ reviews), are backed by 9 VCs, had a 40% revenue increase last year, and topped a valuation of $1B.

We’re a growing, ambitious HealthTech business building the essential digital health partner of tomorrow to empower women, girls, and people who menstruate with the knowledge and support they need to stay well and live better.

Our cycle, ovulation and pregnancy tracking, educational content and anonymised community platform have been trusted for years by millions to help them feel more in control of their health every day.

Now, we’re harnessing the power of data analytics and AI to build a smarter future, one where we all know our bodies better, with an aim to become the essential health partner to women worldwide.

The Job

Build systems that power the #1 Health App for Women

75M+ monthly active users

400M+ downloads

6M+ paid subscribers

We’re not a startup guessing what might work anymore, we’re operating at serious scale. Flo is used by 1 in 4 women aged 18–44 in the US. And we just hit our biggest month ever with 8.6M installs and a 2.8M MAU jump. The engineering behind that? Complex, distributed, secure and yours to help shape.

At Flo, backend engineering is core product work.

We build:

  • Data-driven health insights that genuinely change lives
  • Distributed systems that stay fast, available and scalable under massive real-time demand
  • Privacy-first features like Anonymous Mode -  recognised in TIME’s Best Inventions
  • Tooling and platforms that help Flo’s teams move faster, with fewer bottlenecks

We’re tech-agnostic when hiring for backend. If you’ve built and run distributed systems and want to work in Scala (or already do), great. We’ll support your ramp-up. What matters most: you can solve problems, own outcomes, and keep learning.

Your Experience

You’ll thrive here if you:

  • Have 7+ years’ experience building distributed backend systems
  • Know what it takes to make systems fast, reliable and secure and when to prioritise each
  • Are fluent in Java, Scala, Python or similar (and curious enough to learn Scala with us)
  • Get DevOps, databases (SQL and NoSQL) and love designing APIs that just work
  • Have a strong handle on writing clean, documented, version-controlled code
  • Take ownership, show initiative and don’t wait to be told
  • Are product-minded and always thinking about the end-user impact

Bonus if you’ve worked with:

  • Stream processing
  • Public cloud infrastructure (AWS, GCP etc.)

What’s in it for you?

You’ll join a senior engineering team that moves fast, thinks big and builds tech used by millions daily. You’ll work on meaningful problems with real impact - in health, privacy and scale. This isn’t just code for the sake of code. This is building the future of personalised health.

#LI-Hybrid #LI-LM12

Salary Range - gross per month

€5.000 - €8.000 EUR

Salary ranges may vary depending on your skills, competencies and experience.

Reward

People perform better when they’re happy, paid well, looked after and supported. 

On top of competitive salaries, Flo's employees have access to:

  • A flexible working environment with the opportunity to come into the office and work from home
  • Company equity grants through Flo’s Employee Share Option Plan (ESOP)
  • Paid holiday and sick leave 
  • Fully paid female health and sick leave, in addition to holiday and regular sick leave
  • Workations - an opportunity to work abroad for two months a year
  • Six months paid maternity leave, and one months paid paternity leave (subject to qualifying conditions) inclusive of same-sex and adoptive parents
  • Career growth, progression, and learning development resources
  • Annual salary reviews
  • Unlimited free premium Flo subscriptions
  • A whole host of other benefits (health/pension/social schemes)

 

Our Culture

We’re problem solvers, we’re adaptable, we’re empathy driven and results led. 

People here like working in a fast-paced, multi-national, multi-cultural and ever changing environment. Everyone has an impact on a powerful mission, and is happy to roll their sleeves up to ideate solutions and put them in place. Being part of a  growing business means that sometimes it's not easy and we work hard, but our mission is always at the forefront of what we do. 

Diversity, Equity and Inclusion

The strength of our workforce is in the diverse backgrounds of our employees, and Flo is committed to applying its equal opportunities policy at all stages of recruitment and selection. This means recruitment and selection of talent into Flo Health companies is only based on individual merit and qualifications directly related to professional competence. Shortlisting, interviewing, and selection will always be carried out without regard to gender identity or expression, sexual orientation, marital or civil partnership status, color, race, nationality, ethnic or national origins, religion or beliefs, ancestry, age, veteran status, mental or physical disability, medical condition, pregnancy or maternity status, trade union membership, or any other protected characteristics.

By applying for the above role, you confirm that you have reviewed our privacy notice for job applicants: https://flo.health/privacy-policy-for-job-applicants 

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