Freelancer profile translated to English.
Back to original languageAbout Jens
🚀 Fullstack Developer (8+ years of experience) | Robust Go Backends & Modern React/Next.js Frontends
Are you looking for a Fullstack Developer who not only writes clean APIs but also masters frontend performance, sets your product apart from the competition, and delights your users?
As a freelance software developer, I combine the best of both worlds: performant, highly scalable backends with Go (Golang) and interactive, user-friendly frontends with React and Next.js. With over 8 years of professional experience, I help startups, agencies, and companies build future-proof web applications from scratch or scale existing systems.
In addition to classic fullstack development, I bring an eye for creative frontend and UI/UX – including interactive 3D elements (Three.js/WebGL) if needed, to give your application that certain something. My goal: Products that shine technically and make users HAPPY.
🛠 MY FOCUS & TECH STACK
• Backend & APIs: Go (Golang), REST APIs, gRPC, Node.js, PostgreSQL / MongoDB
• Modern Frontend: React, Next.js, TypeScript, TailwindCSS, State Management (Zustand, Redux)
• Creative Frontend: Three.js, WebGL (for interactive 3D features)
• DevOps & Tooling: Docker, Git, CI/CD, Cloud Hosting (AWS, GCP, Vercel)
💡 WHAT YOU CAN EXPECT FROM COLLABORATION:
1. End-to-End Development: From database architecture and API design in Go to pixel-perfect React frontend.
2. Performance & SEO: Lightning-fast loading times through Server-Side Rendering (SSR) with Next.js and optimized Go services.
3. Product Differentiation: Creative input and technical expertise to make your web app stand out.
4. Transparent Communication: Agile working, direct communication, and absolute reliability.
💬 Let's discuss your project!
Simply send me a message for a non-binding introductory meeting. I look forward to implementing your project together!
German
Native or bilingual
English
Fluent
Remote only
Primarily works remotely
Experience
- AidaFullstack Software DeveloperDIGITAL AND ITJanuary 2026 - May 2026 (4 months)Böblingen, Germany- System Design & Backend: Developed a modular HR platform using Go, implementing CQRS and Event Sourcing patterns with PostgreSQL.- Architecture: Led the end-to-end technical design of the platform and successfully integrated/modernized complex legacy systems.- Plugin Architecture: Architected an extensible plugin system using WebAssembly (Wasm), featuring React Slots and custom configuration logic.- Frontend Development: Built high-performance, reactive interfaces with React & TypeScript. Implemented asynchronous UI updates driven by the event-based backend, utilizing TanStack Query for seamless data synchronization.-Infrastructure: Managed the full application lifecycle with Docker-based containerization.
- Tempest GmbHSenior Frontend DeveloperSOFTWARE PUBLISHINGJanuary 2023 - June 2023 (5 months)Berlin, GermanyWorked on the core frontend of a privacy-focused search engine, focusing on user experience, performance, and modern web standards.Key Achievements:• Engineered frontend features for the private search application with a strong emphasis on page speed, Core Web Vitals, and SEO.• Integrated interactive map components and localized search results to improve geographical user intent.• Structured type-safe and modular application layers using TypeScript.• Built and maintained comprehensive automated End-to-End (E2E) testing flows with Cypress.
- Seitenbau GmbHSenior Frontend DeveloperPUBLIC SECTORFebruary 2021 - December 2022 (1 year and 10 months)Konstanz, GermanyLed the frontend migration of large-scale public administration portals to highly accessible, modern React architectures.Key Achievements:• Migrated a legacy Java Liferay portal system to a modern React & TypeScript SPA communicating with REST APIs (service-bw.de & amt24.sachsen.de).• Developed and organized a shared component library with Storybook to ensure layout consistency across portals.• Implemented robust testing strategies using Jest (Unit) and Cypress (E2E) to secure stability for public services.• Ensured strict compliance with high web accessibility guidelines (a11y / BITV 2.0).
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Education
- Specialist Application Development 2.1IHK Karlsruhe2014- Third level support for Finance Operation - Introduce AOP in the Billing Development to use a control system from Java - Create a presentation about the Project Management Process in the Business System Department - Update the UX Guide Line for Server Development, Attending conferences to exchange knowledge - Final Project in Server Development: Developing a Control Panel for 1and1 Server Monitoring Customers as Java Portlet
Certifications
- MySQL 5.6 DeveloperBBS Montabaur2013