Senior Full Stack Software Engineer (f/m/d) - React, Node.js

We use AI to accelerate – not to replace thinking.
We design the system, steer the output, and take responsibility for what we ship.
Fast where it makes sense. Careful where it matters.

Activities

You’ll join our UI Engineering team and take ownership of full-stack projects that power our adtech ecosystem.
This isn’t just about coding – it’s about collaboration, technical ownership, and making an impact.

Here’s what your day might look like:

• Build and maintain modern React frontends and Node.js APIs with TypeScript.
• Design and implement REST or GraphQL APIs that scale efficiently.
• Collaborate closely with backend engineers, designers, and product owners to translate requirements into elegant solutions.
• Write clean, maintainable, and well-tested code – with automated tests as a natural part of your workflow.
• Contribute to architecture decisions and best practices – we value opinions backed by experience.

Requirements

• 5+ years of hands-on experience in full-stack JavaScript development.
• Deep knowledge of Node.js (framework e.g. Koa, Express or Fastify), TypeScript, React and modern web architectures.
• Solid understanding of relational databases (e.g. MySQL, MariaDB, PostgreSQL or SQL Server), including database design, SQL querying, and REST API development (GraphQL is a plus).
• A strong sense of code quality with mandatory hands-on experience in testing, including frameworks such as e. g. Jest, Vitest, or Node’s built-in testing framework – Clean design and automated tests are not optional.
• Bonus points for experience with: AWS, Jenkins, Grafana, Graylog, Confluence, Jira, Shell scripting

Team

• Ownership over tickets: You’re trusted with real responsibility, not just tasks. No unnecessary bureaucracy, no micromanagement – we rely on you to take things forward.
• Build > Talk: We test what works – not what sounds good. Fail fast, learn faster.
• High standards, low ego: We take our work seriously, but not ourselves. Direct feedback, honest collaboration, no drama.
• Stay sharp: Hackathons, conferences, community – we invest in your growth and keep you at the cutting edge.
• And yes – the fundamentals are covered too: 30 days of vacation + Dec 24 & 31 off, Smart Fridays (4 days week possible), mobility (Germany ticket & JobRad), sports & health offerings, mental health support, corporate benefits, RTL+ access, and more.

Application Process

1. A quick intro call with Sarah (Head of Talent Acquisition @smartclip)
2. Video call with your future manager and a teammate – real talk, no script
3. Meet us in Berlin: hands-on case study, coding challenge (pair programming), or a role play – depending on the role
4. Prompt, honest feedback from Sarah – no ghosting, we promise