REST API Experts in Germany
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Meet FRATCH Experts in Germany, who have recently used REST API
Khalid El Mansouri
Last position:
Lead Architect & Developer at kem-consulting
Development of an agent-based governance platform for the automated assurance of EU AI Act compliance and ODA-compliant orchestration of AI services in complex enterprise environments.
Design and implementation of an agent-based "Mission Control" framework (Aletheia Conductor) for autonomous state monitoring and process control.
Development of "Compliance-as-Code" (CaC) solutions based on OPA/Rego for system-wide enforcement of regulatory guardrails.
Integration of TM Forum ODA standards (TMF630, TMF622, TMF642) to ensure interoperability and standardization.
Building a highly available event-driven architecture using Redpanda and CloudEvents v1.0 for near-real-time event processing.
Implementation of an audit-proof "Evidence Chain" through cryptographic linking of trace logs in preparation for automated audits.
Tech Stack: Java 21 (Quarkus Native), TypeScript (Next.js), Redpanda (Kafka API), CloudEvents v1.0, OPA (Open Policy Agent) & Rego, TimescaleDB, ZincSearch, Redis, TM Forum ODA, Git, GitHub, Clean Code Development, Like-C4.
Johannes Hohenthaner
Last position:
Business Analyst for Riester subsidy management migration at Insurance company
- Analysis of the Riester subsidy GeVos for provider change 2.0 in the AZUR subsidy management system
- Representation of the GeVos in BPMN 2.0 with Draw.io and Adonis
- Analysis of the data sets exchanged with the life insurance policy administration system and migration to the msg data sets
- Design and mapping of the interfaces to the new msg.ZulagenVerwaltung for various Riester subsidy GeVos at data field level
Jens Henneberg
Last position:
Interim CTO (occasional assignments) at Fujitsu / FSAS
Stabilizing an Azure/.NET landscape in live operation.
- Architecture, DevOps, and operational readiness; technical decisions under time pressure
- Azure DevOps, monitoring, ETL/ELT, cloud security, FinOps, and data-mesh-related topics
Technologies: Azure DevOps, .NET, CI/CD, monitoring, FinOps
Kathrin Siegmann
Last position:
Requirements Engineer at Governikus GmbH & Co. KG
- Analysis, documentation, and alignment of requirements. Conducting stakeholder analyses, interviews, and workshops for requirements gathering and validation. Carrying out requirements reviews and working closely with business units and development teams.
Techniques & tools: requirements engineering, stakeholder management, workshop facilitation, system context modeling, requirements reviews, quality scenarios, Miro, Jira, Confluence
Onur Kayir
Last position:
Project Manager & Outsourcing Manager at SENEC GmbH (EnBW Group)
- Building a scalable nearshore IT developer hub (Croatia, Czech Republic, Poland) as an independent company using a BOT model (Build – Operate – Transfer)
- Identifying, selecting, and managing full-service agencies; introducing governance and control mechanisms including KPIs, SLAs, and regular service reviews
- Creating and reviewing data processing agreements and framework contracts in coordination with Legal & Compliance; integrating regulatory requirements (including KRITIS) into process design
- Advising on cloud-vs.-on-premise strategies, data storage, and authorization concepts; supporting procurement with tendering and vendor evaluations
- Change management and process harmonization between internal teams and nearshore partners; reporting to management board, CFO, and CIO
Result: Scalable IT developer hub with an audit-proof governance model, lower operating costs, and faster product development.
Fadi Shoaa
Last position:
Development of a production-ready Enterprise Document AI & Recommendation Platform at Freelancer
- Development of a production-ready Enterprise AI solution for the automated processing of invoices and business documents
- Integration of Azure AI Document Intelligence and LLM technologies into existing business processes
- Development of robust REST APIs for automated document processing and system integration
- Extraction, validation, and storage of structured invoice data in Azure SQL as a base for analytics and machine learning models
- Development of an AI-based recommendation engine with machine learning and deep learning to generate personalized product recommendations based on historical purchase data
- Implementation of logging, monitoring, error handling, and validation mechanisms for stable production use
- Collaboration with business teams to define business rules and integrate the solution into existing enterprise processes
Technologies: Python, Azure AI Document Intelligence, Azure OpenAI, Azure SQL Database, REST APIs, Machine Learning, Deep Learning, OCR, Pandas, JSON, Workflow Automation
Maciej Sawicki
Last position:
Product Owner at Bundesagentur für Arbeit
- As part of the project, the further development of the identity management system was driven forward. This included a comprehensive refactoring of the interfaces to the connected target systems. In addition, several special systems were successfully connected to the IAM to ensure end-to-end identity and authorization management.
- Technical design and solution proposals for IAM system development
- Requirements analysis and requirements management (IREB, BABOK)
- Alignment of the strategy with the future target architecture (TOGAF)
- Prototyping of solutions
- Documentation of requirements (Innovator)
- Analysis and documentation of requirements and creation of process models (UML, BPMN, ArchiMate)
- Modeling of requirements and system functionalities (OOA/OOD, UML)
- Further development of interfaces (SOAP, REST)
- Carrying out architecture reviews
Karen Manukyan
Last position:
Personal AI Engineering Project — Croky AI at Crocky AI
Product:
- Built a production-ready AI platform for generating brand-aware marketing images and videos from product data, user requirements, and uploaded media.
- Own the platform architecture, technical roadmap, API design, security, deployment workflow, operational reliability, and model-provider strategy.
- Developed the core platform in .NET and built supporting AI and workflow prototypes in Python, applying language-independent API contracts and structured interfaces between services and model providers.
- Implemented reliable background processing with RabbitMQ, persisted workflow state, idempotent handling, retries, failure recovery, logging, secure storage, authorization, and credit accounting.
- Made pragmatic build-versus-buy and model-routing decisions based on reliability, latency, cost, and maintainability rather than novelty.
Agent Orchestration & RAG Systems
- Built and compared agent workflows using Microsoft Agent Framework, LangGraph, and LangChain, including tool use, conditional routing, clarification steps, state management, and hand-offs between agents.
- Implemented reusable .NET components for agents, prompts, tools, model providers, structured responses, and retrieval with pyvector, making it easier to change AI providers without rewriting the core workflow.
Harold Tela
Last position:
CPU Watcher — Cloud-Native Monitoring Application at SEUYTEL
Developed a CPU monitoring application using Spring Boot and React, containerized with Docker Compose, with automated infrastructure provisioning using Terraform on AWS.
Stack: Spring Boot, React, PostgreSQL, REST API, Docker Compose, Terraform, AWS
Franz Bauer
Last position:
Product Development (AI) at Own initiative
AI telephone assistant platform
Claude Code, Google AI Studio, Python, LLM / Voice-AI, PostgreSQL
- Conception and hands-on development of an AI-supported telephone assistant platform (voice AI / LLM) – from idea and architecture to MVP/product.
- Built agentic workflows and full automations with Claude Code and Google AI Studio.
- Also delivered AI-supported work in client engagements: used Claude Code for governance documentation, requirement drafts, and automations.
Fred Hauschel
Last position:
Software Architect and Developer at Personal project
A recurring problem in my own AI-supported projects: requirements analysis, use cases, and architecture decisions can be created quickly with AI support, but they remain hard to trace 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 as a continuously linked knowledge graph, traceable from the requirement to the architecture decision – queryable for both people and AI agents alike. Technically based on RDF/OWL and its own MCP server.
Result: MCP daemon running, Docker image automatically published on GHCR, nine hexagonal modules, eleven ADRs (including an open-core licensing model). Requirements engineering and ubiquitous language hexagon active. Publicly available since 07/2026 as a Community Edition under Apache-2.0 (github.com/kogn-io/arknet), together with the Claude Code plugin and the 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
Thomas Polanski
Last position:
Project Manager & Product Owner – M&A Integration at voxa c/o IC Music and Apparel GmbH
- Project management of the legal and system-side integration of Taschenkaufhaus into the Voxa group: conversion of all contracts, accounts, and system access rights on the defined cutover date
- Migration from Microsoft Dynamics NAV 2009 to 2013: analysis of all existing interfaces, redefinition of processes, and coordinated go-live without interrupting operations
- Integration of the complaints and returns process into MS Dynamics NAV 2013; major process simplification through standardization
- Introduction of a new POS system (Shopify POS) in all stores: requirements analysis, configuration, rollout, and employee training
- Use of n8n automation workflows for data reconciliation between marketplaces and ERP; manual processes significantly reduced
Christine Tantschinez
Last position:
Communications Consulting at Storytrend
Most mid-sized companies already have their numbers. What is missing is the translation: a dashboard with forty tiles does not answer a single question that is actually asked in management.
Analysis
- Evaluation of existing data with Python and SQL
- Checking data quality and methodology before making a statement
- The result is an analysis that leads toward a concrete decision
Preparation
- Reports in Power BI and Tableau
- Interactive calculators and visualizations on the web
- Presentations and specialist texts for customers, sales and the public
- Analysis and communication from one source — that
Wolfgang Orgler
Last position:
Business Analyst at Österreichische Post AG
IT systems: Azure DevOps, SharePoint, Opal/Repost, JustinMind, Monday, SAP
Analysis of requirements for branch software
Coordination of intercultural teams
Partly agile project organization
Master data management / DMS
UI/UX design and mockup creation
Requirements documentation
Digitalization of signatures
Stakeholder management and workshop facilitation
Billing/bank transfer
Business analysis / requirements engineering
Matthias Spiller
Last position:
Software Developer and Consultant at CLADE GmbH
- Analysis of the existing CAN communication between microcontrollers
- Analysis of the sensors used and the measured values collected
- Planning the CAN messages for transmitting the measured values
- Iterative adjustment of the microcontroller code to the new CAN messages
- Cross-compilation from x64 to arm64
Discover over 15,000 top freelancers
Statistics of experts using REST API
Aggregated from the professional profiles of matched freelancers.
Experience
17 years
Position duration
2.9 years
Positions per freelancer
12
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Banking and Finance, Automotive
Certification focus areas
Information Technology, Product Development, Project Management
Bachelor's degree or higher
91%
Master's degree or higher
54%
Doctorate
7%
Certifications per freelancer
3
Most common languages
German, English, French
Speak two or more languages
96%
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 Germany 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 Germany using REST API
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
What it covers
REST API work focuses on web interfaces that let systems exchange data over HTTP in a predictable way. A strong specialist designs resource paths, methods, status codes, and payloads so applications, partners, and internal services can talk cleanly. Searchers may also call it a RESTful API or simply REST API.
Typical deliverables
- API design for new products and service layers
- Endpoint reviews for existing REST APIs
- OpenAPI and Swagger documentation
- Auth flows with OAuth 2.0, JWT, and role checks
- Versioning, error handling, and backward-compatible changes
Tooling and ecosystem
REST API specialists often work with OpenAPI, Swagger UI, Postman, Insomnia, and JSON tooling. They also need a solid grasp of HTTP headers, caching, pagination, validation, and serialization. In Germany, many teams expect smooth collaboration with backend, frontend, and platform experts across distributed setups.
When companies bring in help
- An API needs a cleaner contract before a public launch
- Several teams depend on the same backend service
- A partner integration keeps breaking after changes
- Documentation is missing or out of date
- Security, auth, or versioning needs a redesign
Freelance expertise is useful when internal teams are busy or when a project needs a fresh review before release. It is also a good fit for temporary spikes, migrations, and API standardization work.
What strong specialists do
Strong REST API professionals think in resources, not just endpoints. They keep responses consistent, reduce coupling, and make changes safe for clients. Good work is easy to consume, easy to test, and easy to maintain.
What to look for
Look for experts who can explain trade-offs clearly and show real production work. They should know how to handle validation, idempotency, rate limits, and error models without adding unnecessary complexity. Experience with backend services, API documentation, and testing usually matters more than broad tool lists.
Frequently asked questions
Need clarity? These are the questions we hear most often about REST API.
A REST API is used to let software systems exchange data over HTTP in a clear, resource-based way. Companies use it for mobile apps, web frontends, partner integrations, internal services, and public developer interfaces. It is a common choice when different systems need a stable contract.
In practice, REST API and RESTful API are usually used for the same kind of interface. The term RESTful API more clearly points to the design style behind the API, while REST API is the shorter name most people search for. When hiring, focus on how well the expert applies REST rules, not just the label.
A REST API is often simpler to understand and easier to cache than GraphQL, and it is usually lighter than SOAP. GraphQL can help when clients need flexible data shapes, while SOAP may still appear in older enterprise systems. The right choice depends on the contract, team setup, and integration needs.
A strong REST API specialist should know HTTP, JSON, authentication, validation, and API versioning. It also helps to know OpenAPI, Swagger, testing tools like Postman, and how frontend and backend systems consume endpoints. Clean documentation and consistent error handling are part of the job too.
It depends on the scope of the REST API work. A small endpoint review may only need focused experience, while a public API, a migration, or a platform-wide redesign needs someone who has handled production systems before. The key is proven delivery on similar integrations and contracts.
Yes, many REST API experts work remotely very well, especially for design, documentation, reviews, and integration work. In Germany, remote collaboration is common when teams share clear specs and test environments. On-site sessions can still help early in a project or during cross-team workshops.
Ask for examples that show clear endpoint design, stable contracts, and sensible error responses. A good REST API freelancer can explain choices around authentication, pagination, versioning, and backward compatibility in plain language. Strong documentation and test coverage are also good signs.
Common problems in REST API work include inconsistent response shapes, weak error handling, unclear versioning, and missing documentation. These issues make client integration slow and fragile. A capable specialist spots these risks early and keeps the API predictable for consumers.
The average hourly rate of freelancers in Germany who have used REST API in their recent projects is 92 €, which corresponds to a daily rate of about 737 € based on an 8-hour working day.
Of the freelancers in Germany who have used REST API in their recent projects, 91% hold at least a Bachelor's degree, 54% hold at least a Master's degree, and 7% hold a doctorate.
On average, freelancers in Germany who have used REST API in their recent projects have 17 years of professional experience, with a single engagement typically lasting around 2.9 years.
The most common languages among freelancers in Germany who have used REST API in their recent projects are German (97%), English (96%), and French (15%).
The most common industries among freelancers in Germany who have used REST API in their recent projects are Information Technology (94%), Banking and Finance (43%), and Automotive (39%).
The most common business areas among freelancers in Germany who have used REST API in their recent projects are Information Technology (98%), Product Development (92%), and Quality Assurance (56%).
Main locations of FRATCH Experts, who have recently used REST API
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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Philipp Thomaschewski
FRATCH CEO
