Freelance Senior Backend Engineer

Stack

Responsibilities

• ▹Build and evolve services across the learning platform, owning each one from its API contract through to what runs in production
• ▹Take on services you did not write, alongside the people who did
• ▹Design API and data contracts that hold up over time, with type-safe transforms between the API, the domain and persistence
• ▹Run what you build: instrument it, know how it fails, change live data safely and work out why it broke
• ▹Deliver with coding agents as a matter of course, and verify what they produce before you rely on it

Requirements

• ▹Strong, hands-on backend engineering in TypeScript and Node as your primary working language (back-end services, not build tooling and not the server a front-end framework ships with)
• ▹Deep, practical AWS experience in a serverless-first setting: Lambda, API Gateway, DynamoDB and event streaming
• ▹Ability to design API and data contracts and to model a domain, including type-safe transforms at the boundaries between the API, the domain and persistence
• ▹Real production ownership: instrumented your own services, understood their failure modes, changed live data without losing any and worked incidents on systems you own
• ▹Coding agents are part of your daily workflow, and you check their output before you rely on it
• ▹Self-sufficiency: you get unstuck in an unfamiliar codebase without a minder and work within its grain
• ▹Working familiarity with infrastructure as code (Terraform) and CI/CD pipelines, enough to ship and change your own service's delivery
• ▹Python as a secondary language

Nice to have

• ▹Go or Rust for performance-critical components
• ▹Experience with a monorepo build system and shared tooling
• ▹Public technical work, such as open-source contributions or writing

Soft skills

What we offer

• ▹Remote work, Berlin-friendly
• ▹Flexible working models
• ▹Learning budgets
• ▹Free language learning
• ▹Inclusive, supportive environment

About the company

Babbel Labs is an AI-first, independent company within the Babbel group, based in Berlin, building the future of language learning.