AssertJ Experts in Germany
matched in minutes from over 15,000 CVs with the power of AIWork with specialists who modernize enterprise Java test suites, design domain-specific custom assertions, and integrate fluent assertions into complex CI pipelines. Fast matching delivers vetted and immediately available freelancers.
Meet FRATCH Experts in Germany, who have recently used AssertJ
Michael F.
Last position:
Platform Architect (Project lead) at Würth IT
I designed and built a self-service AWS platform for Data Science teams with little or no infrastructure-as-code experience. A team writes about 10 lines of Python and gets a deployable stack with full SDLC release cycle that already follows the governance rules. Networking, encryption, IAM and tagging are decided by the platform, not by each team.
New teams or AWS accounts are onboarded with one pull request. Waste prevention and cost control is built into the defaults: Data scientists don't need infrastructure skills.
- Construct library (AWS CDK, Python). Built a versioned catalog of about 20 hardened constructs for being used in data-science projects with ML context
- Governance as code
- Multi-account, multi-tenant
- Golden-path scaffolding
- CI/CD and supply chain. Built reusable GitHub Actions workflows
- Release engineering
- QA with e2e, contract testing and unit test coverage with each release candidate
Fred H.
Last position:
Software Architect and Developer at Personal project
Recurring problem in my own AI-assisted projects: requirements analysis, use cases, and architecture decisions can be created quickly with AI support, but remain difficult to follow and scattered across Markdown files – knowledge is lost as soon as it is no longer in the context window. arknet turns requirements engineering and architecture knowledge into structured, verifiable data instead of plain text: requirements, use cases, and architecture decisions form a consistently linked knowledge graph, traceable from requirement to architecture decision – queryable by both people and AI agents. Technically based on RDF/OWL and a custom MCP server.
Result: Working MCP daemon, Docker image published automatically to GHCR, nine hexagonal modules, eleven ADRs (including an Open-Core licensing model). Requirements engineering and Ubiquitous Language hexagons are active. Public as a Community Edition under Apache-2.0 since 07/2026 (github.com/kogn-io/arknet), together with the Claude Code plugin and GHCR image; Open-Core model.
Label: Java, Maven, RDF, RDF4J, OWL, SPARQL, Model Context Protocol, Spring AI, Docker, GitHub, Git, Claude Code, Obsidian, DDD, Hexagonal Architecture, ArchUnit, JUnit, AssertJ, Interface Development, Software Architecture, Continuous Integration, Knowledge Management
Marcus B.
Last position:
Java and Quarkus Expert at Large German energy service provider
- Modernization of a large-scale Java enterprise application*
The project is modernizing a complex enterprise application that has grown over many years. The existing Spring-based legacy system runs on Java 8, OSGi, and Eclipse RCP and is being gradually migrated to a modern, maintainable architecture with Java 25 and Quarkus.
Marcus works on analysis, architecture, refactoring, and implementation. One focus is on untangling historically grown structures and dependencies and on building a clean, sustainable Java and Quarkus technology stack.
Tools & technologies: Java 8, Java 25, Quarkus, Hibernate ORM with Panache, EclipseLink, OSGi, Eclipse RCP, Maven, JUnit, Mockito, REST, JSON, Git, Eclipse IDE, IntelliJ IDEA Ultimate, Jira, Confluence
Jens O.
Last position:
Freelance Java Developer / DevOps Engineer at Unpublished defense company
- Extension of OSGi modules in a complex communication solution
- Debugging communication with Wireshark and remotely in the JENS test environment
- Migration of tests from TestNG to JUnit 5 with Mockito and AssertJ
- Updating vulnerable dependencies and improving code quality
- Changes to the Vaadin frontend
- Increasing test coverage
Celil U.
Last position:
ZÜRS Geo 2021 at adesso SE
- Frontend development
- Spring Boot
- Swagger
- Git
- GitLab
- SonarQube
- Docker
- Maven
- Java
- Angular
Tymofii S.
Last position:
Senior Backend Developer at Medavis
- Developed backend features for Modern RIS, a web-based Radiology Information System integrated with the existing Classic RIS via WebView.
- Worked on a modular Spring Boot backend covering clinical workflows such as appointments, examinations, patients, orders, reporting, billing, and inventory.
- Contributed to event-driven architecture using domain events to decouple workflows across backend modules.
- Implemented REST/OpenAPI endpoints, service-layer business logic, DTO mapping, validation, and integration points for the React frontend.
- Worked with PostgreSQL-backed domain models, Liquibase database changes, read/write model separation, and legacy RIS database structures.
- Integrated authentication and authorization flows using Keycloak and OAuth2.
- Added and maintained unit/integration tests using JUnit, Rest Assured, Testcontainers, and project-specific test utilities.
- Supported CI/CD and local development workflows using Maven, Docker Compose, Jenkins, and generated OpenAPI clients.
Tech stack: Java 21, Spring Boot 3.5, Maven, PostgreSQL, Liquibase, Keycloak, OAuth2, REST, OpenAPI/Springdoc, MapStruct, Lombok, Docker, Testcontainers, Jenkins.
Dirk B.
Last position:
Senior Software Developer at congstar
- Mobile app backend development for end-customer mobile management
- Implementation of authentication methods
- Conversion of a monolith into microservices
- Operational support
- Technologies: Kotlin, Quarkus, Microprofile, Jackson, MariaDB, Redis, JSON, XML, SOAP, Maven, Git, GitLab CI, Splunk, Grafana, Jenkins, Kubernetes, Helm, Terraform, Microservices
Ioan D.
Last position:
Senior Software Developer at ING
- Tribe Home, Product Area 4 - Customer in Life, Squad Cybertron.
- Analysis, design, development, and testing of new requirements for Optimmo, construction financing software.
- Analysis, design, development, and testing of the JEE application MWS kredit-baufi.
- Analysis, design, development, and testing of the Wicket Optimmo application.
- Analysis, design, development, and testing of kredit-baufi batch programs.
- Migration of kredit-baufi batches to RHEL9.
- CiL SCS Consumer Pacts with Finagle.
- CiL ScS Touch Point Architecture Integration.
- Team size: 10.
- Tools / Frameworks: OpenJDK Java 17, Kotlin 1.6.0, Azure, Jenkins, Stash, JEE, Gitlab, JIRA, Confluence, git, Spring 6.0, Sping Cloud, Spring Data, Hibernate, JPA, JMS, Kafka, Oracle, PL/SQL, Red Hat Enterprise Linux (RHEL), Maven, REST, JBoss, Intellij IDEA, Wicket 9 and 10, Istio.
Dimitri S.
Last position:
Fullstack Developer, Integrator at Generali Deutschland Versicherung AG
- Developing automated build and deployment processes for the exclusive front office systems
- Integrating the front office systems into the IT infrastructure
- Developing innovative, user-friendly sales software for financial advisors
- Ensuring quality and flexibility through automation and working with CI/CD
- Working according to DevOps principles
- Operating the software together as a team in the AWS cloud and Azure cloud
- Deploying software artifacts to testing and production environments
- Maintaining the test environments
- Performing error analysis and providing information for further root cause analysis
- Maintaining and supporting the build pipeline
- Supporting load testing
- Coordinating the batch execution schedule with batch automation
- Creating concepts to further develop the software packaging process
- Building and delivering components to partners
- Developing GitLab and Jenkins pipelines for building, deploying and integrating components
- Automating processes with Spring Boot applications with a GUI (Thymeleaf, Angular 19)
- Developing RESTful Spring Boot applications with Kotlin and Angular 19, JDBC and REST accesses, data exchange via SFTP, XML (JAXB)
- Designing components using Domain-Driven Design (DDD)
- Replacing cmd and bash scripts with Spring Boot applications with a GUI
- Replacing Java 8 applications with JSP by Spring Boot 3 applications (Thymeleaf, Angular)
- Implementing frontend and backend authentication via Keycloak
- Writing JUnit tests with Mockito
- Increasing code coverage for SonarQube analysis
Rainer B.
Last position:
Senior Developer at RWE Trading
- Development of custom microservices in the power exchanges area based on Spring Boot 3 using PostgresQL, ActiveMQ, Kafka and S3
- Revision and re-implementation of legacy microservices (Scala / Akka) on Spring Boot 3
- DevOps tasks for running the microservices in an AWS runtime environment
- Senior role in the development area in collaboration with the internal client
Adil S.
Last position:
Mobile/Backend Developer at Freelance
- Built a cross-platform mobile application using React Native that interacts with IoT devices via RESTful APIs
- Implemented state management with Redux and integrated IoT-specific components for smooth data visualization and device control
- Developed RESTful APIs using Node.js and Express, utilizing MongoDB for scalable data storage
- Facilitated secure communication between the mobile app and IoT devices, enabling device onboarding, status monitoring, and control commands
- Implemented real-time data synchronization and optimized data flow to minimize latency
Orhan K.
Last position:
kv.digital GmbH
- Backend development work for appointment and doctor services, including the implementation of various requirements for managing doctor appointments.
- SCRUM/Kanban
- Java 21
- IntelliJ Idea
- SpringBoot (MVC, Data JPA, …)
- GIT
- Confluence
- JIRA
- Maven
- CI: Jenkins
- Docker
- ActiveMQ
- MariaDB
- Solr
- Liquibase
- Testcontainer
- JUnit5
- Mockito
Johannes E.
Last position:
Libri GmbH
- Operation and further development of the inventory system for booksellers (Quimus). It is an in-house development by Libri that is sold to customers as Software as a Service. The software is developed in an agile way by two developer teams (about 5 developers each). The software consists of around 25 Java microservices that mainly communicate via messaging and share a common Angular frontend. The application runs on Kubernetes in AWS.
- Technologies used: Java 17 & 21, Spring Boot 2 & 3, Hibernate, MySQL, Spring Cloud AWS, Lombok, AWS SQS, AWS SNS, AWS RDS, AWS S3, DynamoDB, Kubernetes, Docker, OpenSearch, Hibernate Search, Liquibase, Gradle, Terraform, Helm, GitLab CI, Keycloak OAuth2, TypeScript, Angular
- My focus until December 2023: Connecting additional POS systems to the inventory system. Connecting the data warehouse for report display. Extending existing features (goods receipts, invoicing, item management, ...). Operations and DevOps tasks.
- Focus from January 2024: Extracting the product search from the inventory system into a global service to use in other applications. Integrating the product search into the booksellers' online shops (also run by Libri). Importing and providing digital items in the product search.
Bela B.
Last position:
Full Stack Lead Developer, Backend Architect at Telefonica (O2)
The software supports the complete planning and approval of antennas for mobile telephony.
The system was implemented using an event-driven microservice architecture for cloud-native deployment with Quarkus on the backend, Kafka for communication, and Angular for the frontend. Services run on Kubernetes in Google Cloud. A special challenge was synchronizing with the legacy system still used by some users.
Jan M.
Last position:
Interface project at HR Solutions GmbH for Rhineland-Palatinate / BAMF at HR Solutions GmbH
- Developed an adapter from the central foreigner register to an internal application
- REST, JSON, OpenAPI, Spring Boot, Vue, Java, Maven, XAusländer
- Jira/Confluence/GitHub, Scrum+Kanban
Discover over 15,000 top freelancers
Statistics of experts using AssertJ
Aggregated from the professional profiles of matched freelancers.
Experience
22 years
Position duration
1.6 years
Positions per freelancer
16
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Insurance, Automotive
Certification focus areas
Information Technology, Project Management, Product Development
Bachelor's degree or higher
92%
Master's degree or higher
85%
Doctorate
23%
Certifications per freelancer
2
Most common languages
German, English, Spanish
Speak two or more languages
100%
Based on our profile pool as of 29 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Germany 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 Germany using AssertJ
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 29 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
AssertJ 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%)
- Insurance (53%)
- Automotive (47%)
- Banking and Finance (47%)
- Professional Services (47%)
- Retail (47%)
- Energy (41%)
- Healthcare (41%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
Fluent Assertions for Enterprise Java
AssertJ provides a fluent API for writing clear, readable assertions in Java test suites. Originally branched from Fest-Assert, it eliminates nested conditions and delivers precise error messages on test failures. Teams adopt it across unit, integration, and end-to-end testing tiers.
Core Ecosystem Integration
AssertJ integrates seamlessly across modern Java build chains and testing frameworks:
- JUnit 5 Jupiter and TestNG test runners
- Spring Boot Test starter auto-configuration
- AssertJ-DB for relational database state verification
- AssertJ-Guava and AssertJ-vavr for functional collections
- Maven and Gradle automated build environments
When Teams Bring in Freelance Expertise
Organizations in Germany typically engage external specialists during large test suite modernizations or framework migrations. When legacy assertions hide regression causes in mission-critical automotive, financial, or industrial systems, dedicated expertise accelerates test suite refactoring without halting feature delivery.
Custom Assertions and Architecture
Senior professionals write custom assertions that encapsulate complex domain validation rules. They build reusable assertion libraries with custom representation strategies, recursive comparison rules, and soft assertions that evaluate entire entity graphs in a single execution step.
Engineering Profiles in German Projects
Projects across Germany require specialists who bridge test automation with broader enterprise architecture. German teams often expect solid grasp of English alongside working German for documentation and regulatory alignment, combined with proven remote delivery practices across distributed teams.
Hallmarks of Strong Specialists
Top practitioners avoid basic equals assertions and leverage advanced features like filteredOn, extracting, and satisfying conditions. They eliminate fragile tests, enforce clear assertion architecture, and align test code quality directly with production standards.
Frequently asked questions
Questions about AssertJ? Start with the answers below.
AssertJ delivers a fluent, chained API that reads like natural language and produces detailed diagnostic failure messages. Unlike basic JUnit assertions, it provides deep inspection methods for collections, optionals, and complex object graphs out of the box.
While Hamcrest uses static matchers that can produce difficult-to-read syntax, AssertJ relies on method chaining starting with assertThat. This design provides immediate IDE autocompletion, stronger typing, and significantly clearer error messages when assertions fail.
A proficient AssertJ professional brings deep knowledge of Java, JUnit 5, Mockito, and Spring Boot. They also handle build tooling with Gradle or Maven and know how to structure automated pipelines using modern CI platforms.
Teams adopt custom assertions when domain models possess intricate validation rules across multiple fields. An AssertJ specialist creates tailored assertion classes that clarify test intent, reduce duplicate test logic, and produce domain-specific diagnostic outputs.
Companies engage a freelance AssertJ specialist when upgrading legacy suites from JUnit 4 or Fest-Assert to modern frameworks. They help teams refactor fragile tests, standardize assertion standards, and improve build stability in continuous integration environments.
Yes, most companies in Germany facilitate fully remote collaboration for testing and Java modernization work. Organizations running regulated environments, such as German banking or automotive initiatives, may occasionally ask for hybrid kickoffs or initial security onboarding.
Strong use of AssertJ is visible in expressive assertions that avoid manual loops, boolean flags, or nested conditionals inside tests. Top specialists leverage recursive comparisons, soft assertions, and custom condition predicates instead of brittle field-by-field equality checks.
Through the dedicated AssertJ-DB module, AssertJ allows developers to assert table contents, changes, and column values directly against relational databases. Specialists use this to verify persistence layers without writing cumbersome SQL validation code inside test cases.
The average hourly rate of freelancers in Germany who have used AssertJ in their recent projects is 92 €, which corresponds to a daily rate of about 734 € based on an 8-hour working day.
Of the freelancers in Germany who have used AssertJ in their recent projects, 92% hold at least a Bachelor's degree, 85% hold at least a Master's degree, and 23% hold a doctorate.
On average, freelancers in Germany who have used AssertJ in their recent projects have 22 years of professional experience, with a single engagement typically lasting around 1.6 years.
The most common languages among freelancers in Germany who have used AssertJ in their recent projects are German (100%), English (94%), and Spanish (12%).
The most common industries among freelancers in Germany who have used AssertJ in their recent projects are Information Technology (100%), Insurance (53%), and Automotive (47%).
The most common business areas among freelancers in Germany who have used AssertJ in their recent projects are Information Technology (100%), Product Development (100%), and Quality Assurance (65%).
Main locations of FRATCH Experts, who have recently used AssertJ
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.
Berlin Hamburg Munich Cologne Frankfurt Stuttgart Dusseldorf Leipzig Dortmund Essen Bremen Dresden Hanover Nuremberg Request a free demo
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FRATCH CEO
