Jest Expert in Berlin
for reliable JavaScript testing, matched in minutes with vetted and available freelancersHire experts who create maintainable Jest test suites, configure Jest with React and Node.js, and improve coverage in modern JavaScript projects. FRATCH matches you quickly and precisely with vetted, available freelancers.
Meet FRATCH Experts in Berlin, who have recently used Jest
Alexandr K.
Last position:
Technical Co-Founder at Dealyv
- Joined the initial development team and helped transform an n8n prototype into a production-ready 0-to-1 product in a fast-paced environment.
- Owned delivery across CRM and Twilio integrations, customer communication workflows, and administrative interfaces.
- Collaborated on AI evaluation, microservice architecture, and other cross-functional product and engineering topics.
- Supported the CEO across VC communications, customer acquisition, product positioning, onboarding, documentation, pricing, and sales.
Anna M.
Last position:
Freelance Frontend Consultant at Mister Spex
- Developed complex React/TypeScript frontend systems for highly customizable lens products.
- Designed internal tooling for validating and managing product configuration constraints.
- Led accessibility initiatives to align customer-facing applications with EU accessibility requirements.
- Worked extensively in large legacy codebases while incrementally improving maintainability and developer experience.
- Collaborated across multiple teams in an international e-commerce environment.
Aruldass A.
Last position:
Web Module Lead at Mphasis Limited
- Led the end-to-end delivery of enterprise full-stack web applications by driving requirement analysis, solution design, frontend and backend development, database design, API integration, code reviews, team coordination, Agile execution, CI/CD deployments, production support, performance optimization, security implementation, and stakeholder collaboration to deliver scalable, high-quality software solutions.
Maciej R.
Last position:
Full Stack Developer (Freelancer) at Runbuggy
- Led development of RunBot AI assistant autonomously using LLM-powered workflow automation (React, TypeScript, Java, MongoDB, NATS)
- Architected TMS platform providing unified transportation management and real-time logistics visibility with AI processing pipelines
- Designed event-driven microservices architecture supporting marketplace
- Drove architectural decisions and technical leadership across full-stack platform development
Nada S.
Last position:
Freelance Senior Frontend Engineer at Self-Employed
- Senior software engineer focused on React, TypeScript and AI-assisted product workflows
- Build frontend systems for complex SaaS products, internal tools and operational workflows
- Recent work includes AI evaluation tooling, support reliability analysis and developer-focused QA systems
- Available for freelance and contract engagements, especially remote-first projects
Alessandro L.
Last position:
Vue Frontend Engineer at Savills
- Savills is one of the world's leading property advisors with 700+ offices worldwide. In Berlin, I built core digital solutions for the valuation business, replacing legacy Access-based workflows with an enterprise-grade web app built on Vue.js.
- Frontend Architecture & Scalability: Designed scalable Vue + TypeScript frontend architecture for internal enterprise applications, integrating a Symfony backend and interactive maps.
- Legacy Modernization: Led the modernization of legacy jQuery-based systems into maintainable Vue-driven applications, improving performance, maintainability, and efficiency across business workflows.
- PDF Report Workflow Automation: Engineered Twig-based automated PDF generation pipelines that reduced manual report preparation time by ~80%, saving approximately 12h per analyst/month.
- Design System & Frontend: Built a scalable SASS-based design system using mixins, maps, functions, and reusable UI patterns for consistency and long-term maintainability.
Alois R.
Last position:
Senior Fullstack Developer at brandung GmbH
- Opt-in RAG extension over tenant-owned data sources (SharePoint, Confluence) on existing multi-tenant enterprise AI platform
- Architecture: ADRs, solution evaluations, permission strategy, cost modeling
- End-to-end SharePoint and Confluence connectors: OAuth consent flows, token refresh, metadata sync, search integration
- Permission resolution: ACL indexing at ingestion and query-time verification (document-level security)
- Elasticsearch hybrid search (semantic + keyword) with RRF scoring
- RAG chat with context injection and source citations
- Stack: Elastic Cloud, Elasticsearch, Docker, Northflank, Next.js, React, TypeScript, Prisma, Microsoft Graph API, Atlassian REST API, OAuth 2.0
Mario J.
Last position:
Architect / Developer at handyhase
- Overhaul of the entire design and implementation of new UI/UX aspects using React
- Planning of the software architecture and structuring of the project for long-term scalability using Git for version control
Oleg A.
Last position:
Staff Software Engineer at Kpler Germany GmbH
- Delivered a new notifications platform implementation built from scratch to replace existing and upcoming services
- Collaborating with other teams to integrate more domains
Tech stack:
- Data: Scala 3, Apache Kafka, Python, Airflow, Astronomer
- BE-FE: TypeScript, NestJS, Java, Spring Boot, Vue
- Dev-ops: AWS, PostgreSQL, Docker, GitHub Actions, Kubernetes, Helm, ArgoCD
Qaiser A.
Last position:
Freelance Lead DevOps Engineer at Schwarz Gruppe Produktion
Bootstrapping a CloudOps team and building a multi-cloud provider backend for a low-code Internal Developer Platform (IDP) with env zero
Introducing user story mapping, ADRs, milestones, and backlog management
Designing and developing core APIs, setting up CI/CD pipelines, OpenTofu/Terraform scripts
Representing and communicating the team with third-party stakeholders (e.g. env zero)
(Cross-)team coaching on DevOps, software design, Terraform, Golang, and agile practices
Julien L.
Last position:
MLOps Engineer at SAMGEN
- Building and scaling cloud infrastructure on GCP to support a SaaS platform for industrial clients
- Designing and implementing a data-driven DevOps pipeline for streamlined deployment and CI/CD workflows
- Collaborating with Data Science team on MLOps workflow to automate integrated retraining
Max D.
Last position:
Tech Lead, Interim CTO/CPO at MatchDispatch
I worked on automating cold outreach.
- Developed a queue architecture to support the parallel execution of large volumes of background tasks.
- Integrated multiple email delivery providers.
- Implemented an LLM-based data enrichment process.
Technologies: TypeScript, React, Node.js, Next.js, Drizzle ORM, PostgreSQL, Next-Auth, JWT, Docker, Kubernetes, AWS, CloudFlare, Traefik, Groq, Jest, Figma
Adam H.
Last position:
AI Software Engineer at Adevinta
- React
- Python
- Langchain
- GPT
- Typescript
- AWS
- Bedrock
- Docker
- Developing AI powered marketplace tools for a range of solutions across the Adevinta ecosystem.
Jan S.
Last position:
Fullstack Developer at Summify.News
- Developing an AI-enabled platform that summarizes YouTube channels into daily digests with article and podcast formats.
- Built scalable backend in Node.js integrating OpenAI Whisper for transcription and GPT for summarization.
- Implemented frontend in React with TypeScript, ensuring responsive design and accessibility.
- Set up automated deployment pipelines and CI/CD with Docker & GitHub Actions.
Mehul J.
Last position:
Physiobuddy
- Project for mobile users to perform physiotherapy remotely.
Discover over 15,000 top freelancers
Statistics of experts using Jest
Aggregated from the professional profiles of matched freelancers.
Experience
16 years
Position duration
1.4 years (Germany: 1.7 years)
Positions per freelancer
13 (Germany: 12)
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Media and Entertainment, Retail
Certification focus areas
Information Technology, Product Development, Business Intelligence
Bachelor's degree or higher
95% (Germany: 91%)
Master's degree or higher
42% (Germany: 44%)
Certifications per freelancer
1
Most common languages
English, German, Spanish
Speak two or more languages
95% (Germany: 97%)
Based on our profile pool as of 19 Sep 2026.
Daily rate distribution
The chart shows how the daily rates of freelancers in this technology in Berlin are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows how many freelancers charge within that range.
Average rates of experts in Berlin using Jest
Rates are based on recent contracts and do not include FRATCH margin.
The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 19 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
Jest experts industry focus
See which industries our matched freelancers work in most often — every figure is calculated live from the freelancers on FRATCH.
- Information Technology (100%)
- Media and Entertainment (64%)
- Retail (64%)
- Education (55%)
- Banking and Finance (55%)
- Healthcare (36%)
- Manufacturing (36%)
- Advertising (32%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What Jest does
Jest is a JavaScript and TypeScript testing framework for unit, integration and snapshot tests. It is maintained in the React ecosystem and can test application logic, user interface components, services and utility modules. Its built-in runner, assertions, mocking and coverage support keep common testing work in one tool.
Core testing work
Jest experts write focused tests for functions, components and API boundaries. They isolate dependencies with mocks, verify asynchronous behavior, protect rendered output with snapshots and investigate flaky results. They also organize suites so failures point clearly to the behavior that needs attention.
- Unit-test business rules and utility modules
- Test React components and hooks
- Mock services, timers and browser APIs
- Add integration checks for Node.js applications
Ecosystem and setup
Jest commonly works with React, Next.js, Node.js and TypeScript. Projects may use Testing Library for user-focused component tests, ts-jest or Babel for transformation, and ESLint and GitHub Actions around the test workflow. Strong specialists understand module resolution, test environments, code coverage and continuous integration configuration.
When companies need help
Freelance expertise is useful when a product has little test coverage, slow suites or unstable pipelines. Companies also bring in specialists during a React migration, a TypeScript rollout, a major refactor or the separation of legacy tests. In Berlin, remote work is common, while on-site collaboration can help teams align on quality practices and release risks.
- Stabilize flaky Jest suites
- Introduce testing to an existing codebase
- Move tests from another JavaScript runner
- Connect test results to continuous integration
Choosing a strong specialist
Look for professionals who can explain what each test protects and why a mock is appropriate. They should distinguish unit, integration and end-to-end coverage instead of chasing a coverage target alone. Practical evidence includes readable suites, useful failure messages, fast feedback and experience with the project’s framework, build tools and deployment process.
Project collaboration
A Jest engagement works best when the specialist can inspect the repository, understand product risks and agree on a testing strategy with the team. Clear scripts, shared conventions and reproducible environments matter as much as individual test cases. German or English communication can fit Berlin teams, depending on the company and its delivery setup.
Frequently asked questions
Everything clients usually want to know about Jest, in one place.
Jest is used to test JavaScript and TypeScript code, including functions, React components, Node.js services and asynchronous workflows. It combines a test runner with assertions, mocking, snapshots and coverage support.
Jest offers an integrated testing experience with built-in mocks, snapshots and configuration conventions. Vitest can provide very fast feedback in Vite-based projects, while Mocha is more modular and usually relies on separate assertion and mocking tools.
A strong Jest specialist should understand JavaScript or TypeScript, the application framework and the build pipeline. React Testing Library, Node.js, GitHub Actions, Babel, TypeScript configuration and browser API mocking are often relevant as well.
The right Jest freelancer depends on the project’s risk, architecture and existing test suite. Someone improving a small unit-test setup may need a different background from a specialist untangling a large React application with slow, flaky integration tests.
Jest is well suited to remote collaboration because tests, configuration and results can be reviewed in a shared repository and continuous integration pipeline. Teams in Berlin should agree on communication language, review habits and access to local development environments before work starts.
Jest does not replace browser-focused end-to-end tools such as Playwright or Cypress. It is strongest for unit and integration coverage, while end-to-end tests validate complete user journeys across the application and its external services.
Review whether Jest tests describe important behavior, fail for meaningful reasons and remain easy to change. Good work avoids excessive mocking, controls asynchronous cleanup, keeps suites reliable and connects test coverage to actual product risks.
Jest was created at Facebook and became widely associated with the React ecosystem, although it is now used across many JavaScript projects. You may also see it described as Facebook Jest, but Jest is the standard name in current project documentation.
The average hourly rate of freelancers in Berlin, Germany who have used Jest in their recent projects is 83 €, which corresponds to a daily rate of about 662 € based on an 8-hour working day.
Of the freelancers in Berlin, Germany who have used Jest in their recent projects, 95% hold at least a Bachelor's degree and 42% hold at least a Master's degree.
On average, freelancers in Berlin, Germany who have used Jest in their recent projects have 16 years of professional experience, with a single engagement typically lasting around 1.4 years.
The most common languages among freelancers in Berlin, Germany who have used Jest in their recent projects are English (100%), German (91%), and Spanish (14%).
The most common industries among freelancers in Berlin, Germany who have used Jest in their recent projects are Information Technology (100%), Media and Entertainment (64%), and Retail (64%).
The most common business areas among freelancers in Berlin, Germany who have used Jest in their recent projects are Information Technology (100%), Product Development (100%), and Quality Assurance (55%).
Main locations of FRATCH Experts, who have recently used Jest
Our freelancers and interim experts are at home across the DACH region — available on-site in the major business hubs or fully remote. Choose a location to discover matched specialists, local market insights and up-to-date availability.
Hamburg 
Munich 
Frankfurt Request a free demo
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Philipp Thomaschewski
FRATCH CEO
