Stellenbeschreibung

Senior Frontend Developer (React, Next.js, TypeScript) – Freelance

Start: 02.11.2026 | Duration: until 30.04.2027 | Workload: 100% | Location: Remote (95%) / Onsite Berlin (5%) | Contract type: Freelance 

About the Project

For a long-term client in the energy/critical infrastructure sector, nemensis is looking for an experienced Senior Frontend Developer to join a modern web application project. The initiative aims to improve access to technical asset information through intuitive, data-intensive web interfaces, integrated with a headless CMS platform.

As part of the engagement, you will work on frontend architecture, backend-for-frontend development, CMS integration, and quality assurance/automation across the full lifecycle of a modern enterprise web application.

Your Tasks

• Design and evolve frontend architectures based on React, Next.js, and TypeScript

• Build modular, reusable UI components for data-intensive applications, including bulk data import/export, validation, filtering, and visualization features

• Design and implement backend-for-frontend (BFF) components using Nest.js, aggregating REST and GraphQL interfaces

• Implement integration mechanisms with a headless CMS (e.g. Sitecore XM Cloud / Sitecore AI or comparable platforms)

• Apply established engineering standards for maintainability, scalability, and reusability

• Implement and optimize CI/CD build and deployment pipelines using Azure DevOps

• Analyze and optimize frontend performance

• Create and maintain clear technical documentation of architecture, integration concepts, and deployment configurations

Your Profile (Must-Haves)

• Minimum 5 years of professional experience in frontend software development

• Minimum 3 years of practical experience with React, Next.js, and TypeScript

• Minimum 1 year of practical experience with headless CMS platforms (e.g. Sitecore, or comparable solutions)

• Proven experience designing and implementing microfrontend architectures

• Proven experience with backend-for-frontend development using Nest.js

• Minimum 3 years of experience working with REST and GraphQL APIs

• Proven experience with HTML and CSS in modern web applications

• Proven experience with Tailwind CSS and modern UI component frameworks (e.g. Radix UI or comparable)

• Proven experience building data-intensive web applications, including bulk data processing

• Proven experience working within Microsoft Azure environments

• Proven experience with Azure DevOps, including CI/CD pipelines

• German language skills at minimum C1 level

• Very good English language skills

Nice to Have

• Experience with monorepo-based development environments

• Experience with scalable frontend architectures in enterprise environments

• Experience in frontend performance optimization