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Fullstack Developer (m/f/d)

Berlin (Mitte)
Full-time
Permanent employee

These are your tasks

As a Fullstack Developer, you will own product features end-to-end, from technical design and implementation to deployment, monitoring, and continuous improvement. You will work closely with Product, Design, and Engineering to build reliable, scalable, and user-focused solutions across backend and frontend.


  • Design and build new product functionality end-to-end.
  • Own features from scoping and technical design through implementation, testing, deployment, and maintenance.
  • Contribute to architecture decisions and modernise or simplify existing systems.
  • Develop reliable software through automated testing, code reviews, observability, and CI/CD.
  • Ensure safe and backwards-compatible API changes, database migrations, and releases.
  • Collaborate with Product Managers, Designers, and Developers throughout the development lifecycle.
  • Improve product usability, performance, reliability, and development efficiency based on feedback and metrics.
  • Maintain and improve the existing platform, including reducing technical debt and addressing performance or scalability issues.
  • Understand and debug interactions between frontend, backend, databases, asynchronous processes, external services, and infrastructure.

What you bring

  • 3+ years of professional software development experience with strong production experience across backend and frontend.
  • Strong proficiency in PHP, with solid JavaScript/TypeScript skills and hands-on experience with Vue.js.
  • Fluent English (at least C1) - English is the team working language. German is a big plus.
  • Experience building and maintaining REST APIs and integrating external services.
  • Strong knowledge of relational databases, SQL, data modelling, indexing, and query optimisation.
  • Understanding of asynchronous processing, queues, background jobs, and scheduled tasks.
  • Experience with automated testing across backend and frontend.
  • Strong understanding of software architecture, maintainability, performance, scalability, and distributed systems.
  • Practical knowledge of authentication, authorisation, web security, and secure handling of user data.
  • Experience working with and improving a mature codebase, including independently analysing technical problems and proposing pragmatic solutions.
  • Experience taking features from requirements through implementation and into production, including deployment and production debugging.

What we offer

  • Performance-related pay with direct participation in the success of your work
  • 30 days vacation per year
  • A bright, spacious office in the heart of Berlin (near Moritzplatz)
  • A home office arrangement with flexible days (home or office) 
  • A current MacBook Pro and modern equipment (incl. external monitor, keyboard, laptop stand, etc.) - for home office AND office
  • An additional EUR 500 budget to set up your home office so that you can work productively
  • Free lunch twice a week and fresh fruit in the office for the whole team
  • Professional guidance, insights and training in the various topics and tasks as well as in the internal processes of our company
  • Working a fast-growing B2B online company in the heart of Berlin
  • Short official channels, quick decisions and a lot of responsibility
  • A very focused company with high customer and employee satisfaction
  • A relaxed, yet challenging and supportive working atmosphere

About us

InStaff & Jobs GmbH was founded in February 2014 and places staff for temporary assignments throughout Germany. For over 10 years, we have been enabling companies to book staff at short notice and in full compliance with the law - simply, digitally, and efficiently.

Over 17,300 customers have already booked staff through InStaff. Our platform features over 123,000 verified and interviewed staff profiles, allowing us to fill jobs in a wide variety of fields with the perfect fit.
Our quality is reflected in our ratings: over 5,900 customer reviews with an average of 4.9 stars (eKomi) and over 825 employee reviews with 4.8 stars (Google) - primarily from workers who take on temporary assignments for InStaff.

To ensure our continued growth, we are seeking talented and ambitious employees in various fields.