Swagger Experts in Dusseldorf
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Meet FRATCH Experts in Dusseldorf, who have recently used Swagger
Boris Solos
Last position:
Generalist expert for software development at Mercor
- Training the AI models, evaluating images and texts for UI/UX, turning the provided data into insights via OpenAI Feather as part of the machine learning workflow
Technologies: OpenAI Feather
Marc Smyk
Last position:
Fullstack Developer at PLANT-MY-TREE
PLANT-MY-TREE®-per-order
The application enables Shopify merchants to automatically place tree-planting orders for every incoming order. By integrating ecological contributions directly into the purchase process, the manual effort for tracking and billing reforestation initiatives is eliminated. The system increases transparency for end customers through real-time visualizations of the ecological impact directly in the storefront. The architecture is based on a modular monolith with Spring Boot in the backend and an integrated React app inside the Shopify admin area. The solution uses webhooks to capture order data in an event-driven way and integrates the weclapp ERP system for automated monthly invoicing. An app proxy mechanism provides dynamic statistics such as CO2 compensation and planted trees without any performance loss for the merchant shop.
Tasks:
- Design of the modular software architecture based on Spring Modulith to ensure high maintainability
- Development of the event-driven business logic for evaluating Shopify orders via webhooks
- Implementation of automated invoicing by connecting the weclapp REST API
- Building the frontend using React Router and Shopify App Bridge for native integration
- Design of the database model and implementation of the persistence layer with JPA/Hibernate and Prisma
- Integration of internationalization processes for global use in the frontend and email communication
- Automation of deployment processes using Docker and GitLab CI/CD
Project skills: Java 25, Spring Boot, Spring Security, Spring Modulith, Hibernate, JPA, REST API, PostgreSQL, Maven, Liquibase, React, TypeScript, React Router, Vite, Node.js, Prisma, Zod, Docker, Docker Compose, GitLab CI/CD, Shopify CLI, Shopify App Bridge, Polaris, weclapp, i18next, Lombok, Vitest
Alexander Rautzenberg
Last position:
Business Analyst at Financial Services Provider Landesbank
The Helaba ATLAS project aims to modernize core systems and make them future-proof. As part of the subproject, the existing legacy system for international payments is being replaced by a modern web-based application.
- Analysis of functional and technical requirements
- Analysis and optimization of business processes
- Process modeling
- Preparation and facilitation of workshops
- Defining project scope and prioritizing requirements
- Business process management (analysis, modeling, and optimization)
- Specification of user stories
- Designing business and authorization concepts
- Testing and acceptance
- Designing mockups in Figma
- Creating the UI/UX style guide for web applications Approach: Scrum (agile) Technologies: Jira, Confluence, MS Teams, Conceptboard, Java, Vaadin, Figma
Mitali Soti
Last position:
Freelancer at Fintom8 Fintech AI UG
- Built and launched the AI-powered “E-Invoice Corrector,” an intelligent system for validating and correcting invoices, using Python, FastAPI, and machine learning. The system is now live at Fintom8.
- Converted the Corrector into a fully functional API, published with Swagger documentation for easy access and integration by internal and external consumers.
- Designed, experimented with, and optimized advanced LLM prompts and meta-prompting strategies to improve automated reasoning, error correction, and decision-making in agent workflows.
- Wrapped and integrated existing APIs within the Google Agent Development Kit (ADK) framework to enhance automation capabilities and conversational AI workflows.
- Implemented comprehensive unit testing using pytest and unittest, and employed breakpoint debugging (VS Code, pdb) to ensure code reliability, maintainability, and smooth runtime execution.
- Utilized Pydantic and Tabulate for structured data validation, API schema management, and clear tabular data representation in testing and debugging workflows.
- Pursuing the Google Cloud Professional Certificate.
Jan G.
Last position:
Master Data Application at confidential
Visualization, search, and maintenance of various types of master data, providing them via a REST API, and implementing a variety of import and export formats.
Implementation, architecture, project management.
Technologies and tools: Angular (Signals, Signal Store, swagger-codegen, standalone components), Java, PostgreSQL, ActiveMQ, JavaScript, Spring Boot (Spring Core, Spring MVC, Spring Data/JPA via Hibernate, Spring Security, Spring Modulith), JUnit, Flyway, QueryDSL, GraphQL, REST API, Node, npm, Maven, SonarQube, GitLab CI/CD pipelines, Docker, Nexus, OpenAPI + Swagger UI, Keycloak, OAuth2, OpenID Connect, IntelliJ IDEA, Jira, Confluence.
Anouar Taoussi
Last position:
Fullstack Developer Java/Spring Boot at Snipes SE (Deichmann Group)
- Migration of a .NET Core loyalty program for Snipes, used by mobile cash registers in Snipes stores
- Part of the customer’s digitalization strategy in an agile, cross-functional team with a high level of ownership
- Connecting interfaces to third-party systems (e.g. Brandung, CDS)
- Quality assurance through automated tests
- Carrying out developer, unit, and integration tests
- Patterns & methods used: Clean Code, microservice architecture, agile development with SCRUM
- Technologies & tools used: Spring Boot, Java 23, Java Persistence API (JPA), Azure DevOps, Azure Key Vault, Azure PostgreSQL, Docker & Kubernetes, Git, Graylog, Grafana, JUnit, SonarQube, Jira, Confluence, Prometheus, GitLab, GitLab CI/CD, Visual Studio Code
Andreas Grutz
Last position:
Senior Fullstack .NET (Core) & Angular Developer at IT service provider
- Supported an agile team in the development of a new CRM tool
- Web frontend development (Angular 17 with MDB-Bootstrap, microfrontends, DDD)
- Backend development (C# & .NET 7-9, MongoDB, MassTransit, RabbitMQ, Elasticsearch, microservices, DDD)
- Coordination with stakeholders & product owners
- Assisted in sprint planning
Discover over 15,000 top freelancers
Statistics of experts using Swagger
Aggregated from the professional profiles of matched freelancers.
Experience
18 years (Germany: 19 years)
Position duration
1.4 years (Germany: 1.7 years)
Positions per freelancer
16 (Germany: 15)
Top business areas
Information Technology, Product Development, Business Intelligence
Top industries
Information Technology, Retail, Banking and Finance
Certification focus areas
Information Technology, Human Resources, Project Management
Bachelor's degree or higher
100% (Germany: 89%)
Master's degree or higher
60% (Germany: 54%)
Certifications per freelancer
2
Most common languages
German, English, Arabic
Speak two or more languages
100% (Germany: 97%)
Based on our profile pool as of 30 Aug 2026.
Daily rate distribution
The chart shows how the daily rates of freelancers in this technology in Dusseldorf 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 Dusseldorf using Swagger
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 30 Aug 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
About the technology
API documentation
Swagger is widely used to document REST APIs in a way that both specialists and other teams can read. It helps turn endpoints, request bodies, and responses into clear API contracts. Companies use it to reduce guesswork before integration starts.
OpenAPI workflow
In practice, many teams now work with Swagger as part of the OpenAPI workflow. That includes writing and reviewing specs, generating interactive docs, and keeping descriptions aligned with the real service. Strong professionals know when to edit the spec and when to fix the API.
Common tasks
- Define endpoints, parameters, and response models
- Maintain Swagger UI for internal or external teams
- Validate spec changes against implementation
- Support versioned APIs and release notes
Where it fits
Swagger is a good fit for systems that expose REST APIs to web apps, mobile apps, partners, or internal tools. It is also common in regulated or document-heavy environments where teams need a stable contract. In Dusseldorf, it often shows up in software product work and enterprise integration projects.
What strong experts bring
Strong Swagger professionals understand API design, JSON, YAML, and the OpenAPI specification. They write documentation that stays usable after the first release, not just on launch day. They also spot mismatches early, before frontend or integration work slows down.
When to hire
Bring in freelance expertise when an API lacks clear documentation, when teams disagree on request and response shapes, or when an old Swagger setup needs cleanup. Remote work fits most documentation tasks well, while on-site sessions in Dusseldorf can help when teams need quick alignment with backend, frontend, and product specialists.
Frequently asked questions
Before you brief your next project: the most common questions about Swagger.
Swagger is used to describe and document REST APIs so other specialists can understand how to call them. It is common for internal services, partner integrations, and public developer portals. Many teams use it to keep API design and implementation aligned.
Swagger is the older name many people still use, while OpenAPI is the current specification behind most modern workflows. In practice, teams often talk about Swagger UI, Swagger Editor, or an OpenAPI file as part of the same setup. A good freelancer should understand both terms and how they relate.
A strong Swagger freelancer can write or repair API specs, document endpoints clearly, and spot gaps between the spec and the live service. They should be comfortable with YAML or JSON and know how to keep documentation readable for other specialists. If needed, they can also set up Swagger UI for internal use.
Swagger work usually goes with REST API design, OpenAPI, YAML, JSON, and basic backend understanding. Many professionals also know authentication flows, versioning, and documentation review habits. That mix matters because the best spec is only useful when it matches real behavior.
A simple Swagger cleanup can be handled by a specialist who knows API docs well and has worked with OpenAPI before. Larger projects need someone who can model complex responses, manage multiple versions, and work with several teams at once. The key is not a title, but proof of clear API work.
Most Swagger tasks can be done remotely because the work is usually spec writing, review, and documentation updates. On-site time in Dusseldorf helps when several specialists need to align on API structure, naming, or release scope quickly. Many teams use a mix of both.
Good Swagger documentation is accurate, consistent, and easy to use without extra explanation. The spec should match the live API, include realistic examples, and make errors, auth, and edge cases easy to understand. If other specialists can integrate without asking many follow-up questions, the work is strong.
Swagger is most often compared with manual API docs, Postman collections, and other OpenAPI-based tools. The real choice is usually between documentation that is kept in sync and documentation that drifts from the code. A good expert will help you pick a setup that fits the team’s release process.
The average hourly rate of freelancers in Dusseldorf, Germany who have used Swagger in their recent projects is 78 €, which corresponds to a daily rate of about 621 € based on an 8-hour working day.
Of the freelancers in Dusseldorf, Germany who have used Swagger in their recent projects, 100% hold at least a Bachelor's degree and 60% hold at least a Master's degree.
On average, freelancers in Dusseldorf, Germany who have used Swagger in their recent projects have 18 years of professional experience, with a single engagement typically lasting around 1.4 years.
The most common languages among freelancers in Dusseldorf, Germany who have used Swagger in their recent projects are German (100%), English (100%), and Arabic (14%).
The most common industries among freelancers in Dusseldorf, Germany who have used Swagger in their recent projects are Information Technology (100%), Retail (86%), and Banking and Finance (71%).
The most common business areas among freelancers in Dusseldorf, Germany who have used Swagger in their recent projects are Information Technology (100%), Product Development (100%), and Business Intelligence (71%).
Main locations of FRATCH Experts, who have recently used Swagger
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 Request a free demo
Get in touch with the FRATCH team and we will get back to you within 4 hours.
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We always have the time for a call or email!
Philipp Thomaschewski
FRATCH CEO
