Senior Full-stack Engineer (backend-heavy)

We power people’s progress.

At Preply, we’re all about creating life-changing learning experiences. We help people discover the magic of the perfect tutor, craft a personalised learning journey, and stay motivated to keep growing. Our approach is human-led, tech-enabled - and it’s creating real impact.

We’ve just reached unicorn status with a $150M Series D, accelerating our vision to transform education through human-led, AI-enhanced learning. Today, 100,000+ tutors teach 90+ languages to learners in 180 countries - and we’re only getting started. As a category-defining company, we’re shaping what the future of learning looks like at global scale.

Every Preply lesson sparks change, fuels ambition, and drives progress that matters. Joining Preply means helping define the future of education at global scale, and building something that truly matters for millions of people, every day.

What you’ll be doing

You will work in a cross-functional team alongside Product Managers, Product Designers, UX Writers, Data Analysts, Engineering Managers, Engineers, and other stakeholders to deliver meaningful outcomes for learners and tutors. As a Senior Full Stack Engineer, you will combine hands-on execution with technical leadership, helping shape both product direction and engineering excellence through initiatives that drive customer and business impact, including, but not limited to:

• Back-end Development: Develop and own backend features using Python/Django, supporting the creation of new backend services as well as design, create, and/or troubleshoot integrations with third-party vendors.;

• UI Development: Develop and evolve frontend experiences in React/Typescript, contributing to experimentation frameworks and helping establish frontend engineering best practices;

• Implementation & Ownership: Lead complex initiatives from discovery through deployment, taking ownership of solutions throughout their lifecycle and balancing immediate product needs with long-term sustainability;

• Raising the Bar: Drive engineering excellence through mentorship, architectural reviews, and the adoption of best practices across frontend and backend development;

• Data-Driven Product Development: Partner closely with Product, Data, and UX teammates to identify opportunities, validate hypotheses, and maximize customer value through experimentation and measurable outcomes;

• System Design: Shape architectural direction for complex systems, making technical decisions that improve scalability, reliability, maintainability, and developer productivity;

• Prioritisation & Decision-Making: Navigate ambiguity, evaluate trade-offs, and align technical investments with business objectives and customer impact;

• Technical Leadership: Influence technical direction beyond your immediate scope, collaborating with engineers, managers, and stakeholders to drive alignment and successful delivery;

• Chasing Excellence: Continuously raise the quality bar through craftsmanship, curiosity, continuous learning, and a commitment to helping others grow.

What you need to succeed

• Full-Stack Expertise: This is a backend-heavy full-stack role, with approximately 60% of the work focused on backend development and 40% on frontend development;

• AI Expertise: Deep, hands-on expertise in Agentic AI. Able to redesign how the team builds software across the full SDLC, not just code generation. Builds reusable AI assets that your team can adopt, and delegates reasoning-heavy work while reserving judgment for architecture, business logic, and security. You set up the AI quality gates and you challenge existing engineering workflows and propose AI-based alternatives.

• Scalable Systems & Architecture: Experience designing and evolving large-scale web applications, including well-designed APIs, distributed systems, high-volume data flows, and scalable architectural patterns. Ability to make sound technical trade-offs that balance short-term delivery with long-term sustainability;

• Technical Leadership: Demonstrated ability to influence technical decisions, drive engineering best practices, and contribute to architectural direction within your team;

• Product & Business Impact: Strong product mindset with the ability to translate ambiguous business challenges into scalable technical solutions, using experimentation, data, and customer insights to guide decisions;

• Proactive Problem-Solving: Comfortable navigating ambiguity and independently solving complex technical and product challenges, while knowing when to engage others to maximize impact;

• Ownership & Accountability: High level of self-organization, ownership, and responsibility, with a track record of driving initiatives from concept through delivery and measurable outcomes;

• Collaboration & Communication: Excellent collaboration, stakeholder management, and communication skills, with the ability to work effectively across engineering, product, design, and data functions. English level B2 or higher;

• Engineering Excellence: Experience working in a cross functional team, contributing to code and design reviews, and helping raise the engineering bar through knowledge sharing and technical leadership;

• Operational Excellence: Understanding of observability, reliability, monitoring, and operational best practices, with willingness to participate in your squad’s on-call rotation (1 week every 5 weeks);

Why you’ll love it at Preply

• An open, collaborative, dynamic and diverse culture;

• A generous monthly allowance for lessons on Preply.com, Learning & Development budget and time off for your self-development;

• A competitive financial package with equity, leave allowance and health insurance;

• Not in Barcelona? We offer an attractive relocation package to join us in our Preply Barcelona Hub;

• Access to free mental health support platforms;

• Access to Gympass-partnered wellness and gym centers throughout Spain to promote and support well-being and physical health;

• The opportunity to shape the lives of learners and tutors through language learning and teaching in 175 countries (and counting!).