Senior Backend Engineer (all genders)

• Strong, hands-on backend engineering in TypeScript and Node as your primary working language today. We mean back-end services: not build tooling, and not the server a front-end framework happens to ship with.
• Deep, practical AWS experience in a serverless-first setting. Lambda, API Gateway, DynamoDB and event streaming are our daily tools, and we want someone who has designed against them rather than only deployed onto them.
• The 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. You have instrumented your own services, understood their failure modes, changed live data without losing any, and worked incidents on systems you owned.
• Coding agents are part of your daily workflow, and you check their output before you rely on it. You are neither dismissive of them nor careless with them.
• Self-sufficiency. You get yourself unstuck in an unfamiliar codebase without a minder, and you work within its grain rather than rewriting what you have not yet understood.
• Working familiarity with infrastructure as code (Terraform) and CI/CD pipelines, enough to ship and change your own service’s delivery. This is not an infrastructure role, so depth here is not the bar.
• Python as a welcome secondary language. Some of our services are Python, and a Labs engineer can expect to touch them.

Nice to have

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

Babbel Labs is building the future of language learning. We are an AI-first, independent company within the Babbel group, based in Berlin. Our teams bring AI, research and product together to ship experiences that set a new standard for how people learn., Babbel Labs is rebuilding how learning content is created, stored and served, and how we decide what a learner sees next. The architecture for that is being set now, by a small number of engineers, and this role is one of them.

You will build and run the services behind it, in a serverless-first TypeScript and Node stack on AWS, owning them from the contract at their edge to their behaviour under load.

This is a senior individual-contributor role. You will design, build, ship and operate, and the seniority shows in the decisions you own rather than in a team reporting to you.

How you’ll make an impact

• Build and evolve services across our 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 be the person who works out why it broke.
• Deliver with coding agents as a matter of course, and verify what they produce before you rely on it.