About Flo
400M+ downloads. 75M+ monthly users. A decade of building – and we’re still accelerating.
Flo is the world’s #1 health app on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, we became the first product of our kind to reach a $1B valuation in 2024 – and we’re not slowing down.
With 6M paid subscribers and the highest-rated experience in the App Store’s health category, we’ve spent 10 years earning trust at scale. Now, we’re building the next generation of digital health – AI-powered, privacy-first, clinically backed – to help our users know their body better.
The Job
Build systems that power the #1 Health App for Women.
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 is complex, distributed, and secure.
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, recognized 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 prioritize 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 personalized health.
#LI-Hybrid #LI-LM12
How we work
We’re a mission-led, product-driven team. We move fast, stay focused and take ownership – from brief to build to impact. Debate is encouraged. Decisions are shared. We care about craft, ship with purpose, and always raise the bar.
You’ll be working with people who take their work seriously, not themselves. It takes commitment, resilience, and the drive to keep going when things get tough. Because better health outcomes are worth it.
What you'll get:
- Competitive salary and annual reviews
- Opportunity to participate in Flo’s performance incentive scheme
- Paid holiday, sick leave, and female health leave
- Enhanced parental leave and pay for maternity, paternity, same-sex and adoptive parents
- Accelerated professional growth through world-changing work and learning support
- Flexible office + home working, up to 2 months a year working abroad
- 5-week fully paid sabbatical at 5-year Floversary
- Flo Premium for friends & family, plus more health, pension and wellbeing perks
Diversity, equity, and inclusion:
Our strength is in our differences. At Flo, hiring is based on merit, skill and what you bring to the role – nothing else. We’re proud to be an equal opportunity employer, and we welcome applicants from all backgrounds, communities and identities. Read our privacy notice for job applicants.
Apply for this job
Please apply through the official Flo Health jobs page on Greenhouse. Fill out the application form with all required details including personal information, resume/CV, cover letter, and additional demographic information as requested. Confirm that you live full-time in Lithuania and your ability to commute to the office in Vilnius 3 times per week as stated in the form.
The direct link to the job application is: Flo Health Senior Backend Engineer Application