Software Engineer (Experimentation Squad) in Barcelona


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Job Description

Preply is a global language learning marketplace, connecting 15,000+ tutors with millions of learners from all over the world. Since the company launched in 2012, students have signed up to more than five million lessons.

Backed by some of the world’s leading investors, Preply is on a mission to shape the future of effective learning. Fueled by a belief that live engagement with a teacher is still the most effective way to learn a new skill, Preply is building a personalized learning space that will enable individual learners to reach their goals in the fastest way possible.

Powered by a tenfold increase in revenues over the last three years, Preply now has 200+ employees of over 25 nationalities based between Barcelona and Kyiv. Preply is driven by a culture of experimentation and data-driven learnings, focused on building best-in-class consumer and enterprise solutions.  

As the company looks to increase momentum and scale geographically, this is a unique opportunity to join one of the most vibrant and attractive start-up communities in the world.

We are currently looking for a Software Engineer in Experimentation Squad to join our Platform tribe.

Here in Preply we a/b test most of our changes on production, both product and technical before scaling it to all customers.

Platform tribe owns the whole infrastructure that is used to make those business-vital decisions.

We’re using modern stack, you can check it here:

We have diverse technical challenges (sometimes we write about them on our Engineering Blog) that will allow you to develop your skills across the stack.

You, as a part of Experimentation Squad, will:

    • Develop systems that are used by all product and platform squads in their daily work in the decision making process;
    • Tackle problems that occur in highly loaded systems, such as cross-experiment correlation, data consistency, event deduplication, etc.;
    • Design and monitor architecture in a way that will guarantee stability and reliability in the highly variative environment where 60+ developers deploy production 50+ times a day.
    • We work in small teams, thus you will be able to influence system design and contribute a lot in the company's growth, also we promote self-direction to work on meaningful projects, while we also strive to create an environment that provides the support and mentorship needed to learn and grow.


    • Establish credibility with the quality of the a/b testing system.
    • Develop new ways of a/b testing (SEO a/b testing, etc.).
    • Own Data pipelines and ensure Data consistency.
    • Support & develop a/b testing interpretation tools.
    • Integrate with 3rd party providers.
    • Collaborate with product teams to help them tackle technical issues with a/b testing.

What we are looking for:

    • Strong knowledge of Python, at least 2+ years experience.
    • SQL hands-on experience.
    • Understanding basics of statistical analysis: p-value, null hypothesis, confidence interval - something you should be familiar with.
    • A passion for analyzing data to inform decisions.
    • Addiction to measuring and monitoring.
    • High code-testing standards.
    • Readiness to take responsibility of systems that directly impact company decision making process.
    • Minimum B2 English level is a must.

What we offer:

    • An opportunity for personal and professional growth, supported by high functioning teams, stellar investors and the exciting challenges that come with joining a company at the start of its growth trajectory.
    • An environment free of bureaucracy and corporate constraints; a culture where your opinion is highly valued and appreciated.
    • An open, collaborative, dynamic and international culture.
    • A monthly allowance for self-development on
    • A competitive financial package, with generous leave allowance and health insurance.

Our values:

    • Human: We speak honestly and directly with compassion and radical candor. We believe every interaction should be friendly, personalized, diverse and inclusive. Above all, we believe fun should be apart of everything we do
    • Customer Obsession: We put our customers first by asking for feedback and analyzing the data to build products they love.
    • Hungry: Our will to win is unmatched. We make bold, data-informed decisions, to quickly deliver value to our customers. We dare to dream big, think like co-owners, and go the extra mile to hire others who share our champion spirit.
    • Humble: We keep our egos low, constantly learn, and trust in data to make smart decisions. We know that our knowledge is imperfect and incomplete, but not stagnant. There's always more to learn from each other, our customers, and the world around us.
    • Curious: We are lifelong learners. Our curiosity helps us to view tough situations more creatively. We kill the noise and go deep on insights. We face challenges head on, and consistently seek opportunities to learn more.
    • Hackers: We’re obsessed with our customer’s problems. We focus on what matters, design with pragmatism, and move with incredible speed to create simple, creative, and scalable solutions.

Diversity is important for us 

Preply is committed to creating a diverse environment and is proud to be an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age or veteran status.


About Preply

  • Edtech

  • Brighton, MA

  • 50-200

  • 2012


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