Senior Back-End Engineer

About the role

You will work in a cross‑functional squad with a Product Manager, Designer, UX Writers, Data Analysts and other engineers to deliver engaging features through A/B tests and build high‑quality products.

Key responsibilities

• Develop and own backend features using Python/Django, including new services and integrations with third‑party vendors.
• Understand customer needs, define solutions with the team and balance short‑term speed with long‑term technical quality.
• Guide the squad in technical decisions, champion best practices such as test culture, code reviews, monitoring and scalability.
• Support occasional small JavaScript/TypeScript tasks and contribute to AI‑augmented development workflows.

Required profile

• Experience with architectural patterns of large, high‑scale web applications (well‑designed APIs, high‑volume data pipelines, efficient algorithms).
• Hands‑on use of Agentic AI as a thought partner, setting quality gates and safety nets.
• Strong troubleshooting skills, root‑cause analysis and implementation of safeguards.
• High level of self‑organization, ownership and responsibility.
• Excellent verbal and written communication in English (minimum B2) and willingness to be on‑call one week every five weeks.

Required skills

• Python
• Django
• Java
• Spring
• Node.js
• Express.js
• Ruby
• Ruby on Rails
• Scala
• Play
• PHP
• Golang
• JavaScript
• TypeScript

What we offer

• Generous monthly allowance for lessons on Preply.com and a learning & development budget.
• Competitive financial package with equity, leave allowance and health insurance.
• Attractive relocation package for candidates outside Barcelona.
• Free mental‑health support platforms and access to Gympass‑partnered wellness centres across Spain.
• Opportunity to shape language learning for millions of users in 175+ countries.