Senior Full-stack Engineer (backend-heavy)

Stack

Responsibilities

• ▹Develop and own backend features using Python/Django, support the creation of new backend services, and design, create and/or troubleshoot integrations with third-party vendors
• ▹Develop and evolve frontend experiences in React/TypeScript, contribute to experimentation frameworks and help establish frontend engineering best practices
• ▹Lead complex initiatives from discovery through deployment, taking ownership of solutions throughout their lifecycle and balancing immediate product needs with long-term sustainability
• ▹Drive engineering excellence through mentorship, architectural reviews and the adoption of best practices across frontend and backend development
• ▹Partner closely with Product, Data and UX teammates to identify opportunities, validate hypotheses and maximize customer value through experimentation and measurable outcomes
• ▹Shape architectural direction for complex systems, making technical decisions that improve scalability, reliability, maintainability and developer productivity
• ▹Navigate ambiguity, evaluate trade-offs and align technical investments with business objectives and customer impact
• ▹Influence technical direction beyond your immediate scope, collaborating with engineers, managers and stakeholders
• ▹Continuously raise the quality bar through craftsmanship, curiosity and helping others grow

Requirements

• ▹Full-stack expertise: a backend-heavy role, approximately 60% backend and 40% frontend
• ▹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, delegates reasoning-heavy work while reserving judgment for architecture, business logic and security; sets up AI quality gates and proposes AI-based alternatives to existing engineering workflows
• ▹Experience designing and evolving large-scale web applications, including well-designed APIs, distributed systems, high-volume data flows and scalable architectural patterns
• ▹Demonstrated ability to influence technical decisions, drive engineering best practices and contribute to architectural direction within the team
• ▹Strong product mindset with the ability to translate ambiguous business challenges into scalable technical solutions using experimentation, data and customer insights
• ▹Experience working in a cross-functional team, contributing to code and design reviews
• ▹Understanding of observability, reliability, monitoring and operational best practices, with willingness to join the squad's on-call rotation (1 week every 5 weeks)
• ▹English level B2 or higher

Soft skills

What we offer

• ▹An open, collaborative, dynamic and diverse culture
• ▹A generous monthly allowance for lessons on Preply.com, Learning & Development budget and time off for self-development
• ▹A competitive financial package with equity, leave allowance and health insurance
• ▹Relocation package to join the Preply Barcelona Hub for those not in Barcelona
• ▹Access to free mental health support platforms
• ▹Gympass-partnered wellness and gym centers throughout Spain
• ▹The opportunity to shape the lives of learners and tutors through language learning and teaching in 175 countries

About the company

Preply is a human-led, tech-enabled learning platform where 100,000+ tutors teach 90+ languages to learners in 180 countries. It recently reached unicorn status with a $150M Series D. The team builds with Python/Django and React and ships 50–60 times per day.