Kotlin Experts in Dortmund
, matched in minutes with vetted, available freelancersHire experts who deliver Android applications, Kotlin Multiplatform products and JVM-based backend services with tools such as Spring Boot, Ktor and Jetpack Compose. FRATCH finds a precise match quickly among vetted, available freelancers.
Meet FRATCH Experts in Dortmund, who have recently used Kotlin
Laurin H.
Last position:
Software Architect (Freelance) at Care4Sure
- Delivered MVP-focused full-stack architecture for a health-sector client: Vite/React frontend, backend services on Google Cloud Run, and Supabase for database plus IAM/authentication.
- Supported product requirements engineering and prioritized cost-aware workload placement, implementing browser-side/edge computation where feasible before moving logic to backend services.
Kersten L.
Last position:
Lead Architect / Lead Developer at Bettles: Sports Betting Platform
- Complete greenfield rebuild across the whole stack — built AI-native: backend in Go and NestJS, PostgreSQL (CNPG) on K3s with GitOps/Terraform; frontend on Angular 22, zoneless.
- Orchestrated coding agents (e.g. Claude Code, Cursor) across the entire lifecycle — architecture, implementation, testing, reviews, documentation — driven by Specification-Driven Development (SDD).
- “Bruno” — LLM commentator persona backed by RAG and MCP for a personality that stays consistent across all generations (match previews, post-match reports, his own virtual bets).
Angular 22 (zoneless, without Zone.js), Claude Code, Claude Code Skills, CNPG, Cursor, Design Tokens (Spec for Code), Docker, Gherkin, Git, GitLab, GitOps, Go, Google Gemini, Grafana, Hetzner Cloud, K3s, Keycloak, Kubernetes, Lighthouse, LLM Integration, Model Context Protocol (MCP), NestJS, Node.js, NPM, Playwright, PostgreSQL, Prometheus, RAG, REST, Specification-Driven Development (SDD), Structured Outputs, Terraform, TypeScript, Vitest
Arkadius S.
Last position:
AWS Pricing Platform / API & Integration Architecture at Porsche Digital
Development and evolutionary further development of a highly available, cloud-native microservice and integration architecture for dealer and retail processes in the Porsche Car Configurator.
Responsibilities
- Development of Java-/Kotlin-based backend, API, and integration components (Spring Boot)
- Integration of internal and external systems via REST/OpenAPI, GraphQL, Apache Kafka, and AWS SQS (synchronous and asynchronous)
- Implementation of stable, high-performance communication and data flows in a cloud-native platform architecture
- Processing of structured data formats (JSON, Protobuf, GraphQL schemas) based on existing API patterns
- Performance optimization of distributed microservices with reduced response times and higher operational stability
- Technical tests (unit, integration, and API tests) as well as error analysis in production-like environments
- AWS Infrastructure as Code with Terraform and AWS CDK
- CI/CD automation (build, test, and deployment pipelines) with GitHub Actions
- AI-supported feature implementation (GitHub Copilot Agent)
Label: Kotlin, Java 25, Spring Boot 4, Protobuf, TypeScript, AWS, Terraform, CDK, Apache Kafka, AWS SQS, REST/OpenAPI, GraphQL, JSON, PostgreSQL, Docker, GitHub Actions, Maven, Gradle, JUnit, Mockito, Testcontainers
Patrik G.
Last position:
Technical Lead Conversational AI at CANCOM
- Technical lead of a team developing agentic chatbot solutions (React, TypeScript, Python, FastAPI)
- Architecture design for multi-LLM dialog systems - focus on maintainability, UX, and autonomous execution
- Stakeholder alignment, CI/CD processes, and AI integration at enterprise level
Rafael K.
Last position:
Senior Android Developer / Team-Lead at IBM Deutschland
- Further development and release support for a white-label ePA component for health insurance companies
- Technologies: Android (Kotlin), Kotlin Multiplatform, Coroutines, Jetpack Compose, MVVM, StateFlow, Gradle, ProGuard
Hendrik B.
Last position:
Lecturer at Front and Fullstack Development Lecturer
- Teaching JavaScript, HTML, CSS, React, NodeJS, MongoDB, MariaDB, and Express
- Designing and preparing lessons
- Classroom teaching and one-on-one coaching
Jan-Niklas F.
Last position:
Founder at Freundt Consulting GmbH
- Porsche AG (2018 – 12/2019): Design and development of native iOS apps in motorsport/Formula E (e.g. travel app and enterprise warehouse management with SAP integration) and e-mobility (Porsche Taycan; development of a native Microsoft Excel data export).
- StarFinanz / Sparkasse (05/2019 – 07/2021): Worked on the banking app (FinTS, HBCI, PSD2, Apple Pay); implemented Apple Pay; implemented a new TAN method; worked with the FinTS backend (PSD2); opened bank accounts via app (eID, VideoID, Authada); designed a new, modern banking experience.
- eBay Classifieds and Adevinta (07/2021 – 06/2023): Packaging & Pricing (premium features for business customers): e.g. markdown; company page; advertising options; multi-tenant design system based on SwiftUI and UIKit.
- Maschinensucher (07/2023 – 12/2023): Fullstack mobile (Android, iOS) and backend (PHP, Yii, Elastic Search) development; implemented search agent push notifications, InstantSearch, and modernized the design.
- Bankverlag (02/2024 - Present): Consulting and fullstack development of white-label apps (iOS / Android / Java Spring Boot) for private banks.
Discover over 15,000 top freelancers
Statistics of experts using Kotlin
Aggregated from the professional profiles of matched freelancers.
Experience
19 years (Germany: 17 years)
Position duration
2.2 years (Germany: 2.7 years)
Positions per freelancer
12
Top business areas
Information Technology, Product Development, Operations
Top industries
Information Technology, Education, Healthcare
Certification focus areas
Human Resources, Information Technology, Project Management
Bachelor's degree or higher
100% (Germany: 93%)
Master's degree or higher
40% (Germany: 56%)
Certifications per freelancer
2
Most common languages
German, English, Spanish
Speak two or more languages
100% (Germany: 98%)
Based on our profile pool as of 16 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Dortmund are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows the share of experts charging within that range.
Average rates of experts in Dortmund using Kotlin
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 16 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
Kotlin 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%)
- Education (86%)
- Healthcare (86%)
- Automotive (71%)
- Manufacturing (71%)
- Insurance (57%)
- Construction (43%)
- Banking and Finance (43%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
Kotlin at a glance
Kotlin is a statically typed language from JetBrains that runs on the Java Virtual Machine and interoperates closely with Java. It is used for Android applications, backend services, desktop software and shared code across multiple platforms. Its concise syntax, null-safety features and coroutine support help teams create readable systems with fewer avoidable runtime errors.
Applications and services
Kotlin fits products that need a modern JVM foundation or a shared codebase across devices.
- Android applications with Jetpack and Jetpack Compose
- REST and GraphQL services with Spring Boot or Ktor
- Kotlin Multiplatform applications for Android, iOS and desktop
- Event-driven services, data pipelines and internal business tools
- Native integrations with Java libraries and enterprise systems
Ecosystem and tooling
Strong Kotlin work depends on more than language syntax. Professionals use Gradle for builds, IntelliJ IDEA or Android Studio for development, and coroutines and Flow for asynchronous work. They may also work with Spring, Ktor, Compose, SQL databases, Kafka, Docker and cloud deployment workflows. Java interoperability is important when an existing system contains established libraries or services.
When companies need specialists
Companies often bring in freelance Kotlin expertise when an Android product needs a stable release path, a Java service is being modernized, or a shared mobile codebase is under consideration. Signs include inconsistent coroutine usage, slow build pipelines, difficult Java integration or a growing backlog of platform-specific fixes.
- A Kotlin migration needs a safe, staged plan
- Mobile and backend teams need a shared technical approach
- A prototype must become a maintainable production service
- Test coverage, build automation or release quality needs attention
What strong professionals deliver
A capable specialist explains trade-offs instead of treating Kotlin as a replacement for every existing tool. They structure modules clearly, handle nullability deliberately, test coroutine-based code and keep build configuration understandable. For Android work, they understand lifecycle behavior, state management, accessibility and performance. For backend work, they design observability, resilience, security and data access into the service.
Working with Kotlin experts in Dortmund
Dortmund companies can collaborate with local specialists on-site or combine occasional visits with remote delivery. Clear documentation, shared planning and dependable review practices matter in either model. German or English communication can be agreed at the start, especially when the work connects local product teams with international contributors. The right professional should show relevant Android, JVM or multiplatform deliverables and explain their role in the result.
Frequently asked questions
Not sure where to start with Kotlin? These answers cover the essentials.
Kotlin is widely used for Android applications, backend services on the JVM and Kotlin Multiplatform products. It also supports desktop software, scripting and integrations with established Java systems.
Kotlin offers concise syntax, built-in null-safety and coroutines while remaining interoperable with Java. Java may still be the practical choice when a team relies heavily on existing libraries, conventions or a large established codebase.
A strong Kotlin professional may also work with Android SDK, Jetpack Compose, Spring Boot, Ktor, Gradle, SQL and cloud services. Experience with testing, CI pipelines, Docker and observability is valuable for production delivery.
The right level depends on the system’s risk and scope, not on a fixed time period. A small feature can suit a specialist familiar with the relevant framework, while a migration or shared mobile architecture calls for proven Kotlin and Java interoperability skills.
Kotlin work is well suited to remote collaboration because source control, automated builds and code review support distributed teams. Dortmund companies should agree on working hours, on-site expectations, documentation standards and whether German or English is used for delivery.
Kotlin is a strong fit for Android products because it works closely with Android tooling and supports modern UI approaches such as Jetpack Compose. Quality still depends on lifecycle handling, accessibility, testing, performance and clear state management.
Review how the Kotlin professional handles architecture, nullability, coroutine cancellation, tests and build configuration. Ask for concrete examples of production decisions, Java integration and how defects or performance issues were investigated.
Kotlin Multiplatform can make sense when mobile or desktop products should share selected domain logic while preserving platform-specific user experiences. A specialist should assess library support, team skills, release processes and the boundary between shared and native code before recommending it.
The average hourly rate of freelancers in Dortmund, Germany who have used Kotlin in their recent projects is 95 €, which corresponds to a daily rate of about 760 € based on an 8-hour working day.
Of the freelancers in Dortmund, Germany who have used Kotlin in their recent projects, 100% hold at least a Bachelor's degree and 40% hold at least a Master's degree.
On average, freelancers in Dortmund, Germany who have used Kotlin in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 2.2 years.
The most common languages among freelancers in Dortmund, Germany who have used Kotlin in their recent projects are German (100%), English (100%), and Spanish (43%).
The most common industries among freelancers in Dortmund, Germany who have used Kotlin in their recent projects are Information Technology (100%), Education (86%), and Healthcare (86%).
The most common business areas among freelancers in Dortmund, Germany who have used Kotlin in their recent projects are Information Technology (100%), Product Development (100%), and Operations (57%).
Main locations of FRATCH Experts, who have recently used Kotlin
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.
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Stuttgart 
Dusseldorf Countries:
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