REST API Expert in Leipzig
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Meet FRATCH Experts in Leipzig, who have recently used REST API
Thomas P.
Last position:
Product Owner & AI Automation Architect (B2B) at Ihre-Hygieneberatung
Development of a digital audit application for inspections in medical facilities. The goal is to connect on-site data collection, voice recording, documentation and downstream processes in one end-to-end, AI-supported workflow.
Design and development of a Flutter audit app with Claude Code for the structured execution and documentation of inspections.
Processing of voice recordings captured in the app through automatic transcription and AI-supported creation of structured inspection reports, followed by an approval process
Connecting various data sources such as email, Odoo 19, attendance records and Google Drive via n8n to automate billing and follow-up processes
Automatic provision of required documents and email delivery through n8n-controlled workflows, including the use of LLMs for text creation
Skills: Flutter, Claude Code, LLM Integration, n8n, Odoo 19, Google Drive, Process Automation
Natascha F.
Last position:
Senior iOS Developer - ANÜ at Stadtwerke München GmbH
- Development of an iOS app that combines public transport and sharing services
- Collaboration in Scrum within a large cross-functional team
- Creation of reusable components with SwiftUI and Combine
- Development of custom solutions for Apple Maps
Frank R.
Last position:
eCommerce Software Developer at WirTube-Shop
- Maintenance and system handover
- Planning and carrying out core and plugin updates
- Developing a plugin to extend invoice creation and payment via Flow Builder
Peter T.
Last position:
Freelance Go-Developer/DevOps-Engineer at IONOS SE
- Implementation of an API for customers to provide NFS shares in the cloud
- Creating Kubernetes operators and services with REST APIs in Go
- Using LinuxKit for provisioning VMs
Sascha W.
Last position:
Lead Product Owner CADKit at Ottobock SE
- Realignment and technical leadership of a CAD web platform for the global digitization of the prosthetics manufacturing process
- Translating the CPO's vision into a technical roadmap and leading an interdisciplinary team of developers, designers, and QA
- Implementing complex 3D interfaces using Vue.js and Three.js
- Global rollout of 8 scalable web apps, increasing production efficiency by 80%
Gwen G.
Last position:
Senior Ruby on Rails & DevOps Developer at Sapiens
Further development of a software solution for managing test requests and test notifications according to §106d SGB V for the Hamburg Association of Statutory Health Insurance Physicians.
- Developed numerous features, performance optimizations, refactoring, error analysis
- Refactored the dev container setup
- Optimized the GitLab CI build pipeline
- Contributed optimizations to the team workflow
Julian H.
Last position:
Working Student / Master's Thesis Student Software Development at Scale GmbH
- Tech-Stack: Python, Qt, tensorflow.js, plotly, Angular, TypeScript, HTML, CSS, Git
Hannes W.
Last position:
intermedix GmbH / CGM Deutschland AG
Rule-based software for managing, planning, and providing promotional materials in the pharmaceutical industry
High performance, high availability
Fullstack, DevOps (CI/CD)
Python, PostgreSQL, Vue.js, Typescript, Docker, Docker-Compose, Nginx
Successfully transformed old Excel-based processes into an optimized product that has been in production since 2024
Mostafa S.
Last position:
Freelance Senior Software Engineer & AI Consultant at Self-employed
- Led the development of a complex geospatial data platform, engineering an end-to-end system for processing and analyzing high-resolution aerial imagery.
- Engineered a scalable backend responsible for on-the-fly map tile serving and running complex data analysis queries using PostGIS and Python.
- Developed and trained custom computer vision models using Python, PyTorch, and YOLOv8 to perform object detection and segmentation on large-scale datasets.
- Built modern, responsive user interfaces and data visualization dashboards using Next.js, TypeScript, and React.
- Gained practical expertise in geospatial libraries such as GDAL and Rasterio for processing and manipulating raster and vector data.
- Managed the entire project lifecycle, from initial technical architecture and database design to final deployment using Docker.
Andreas M.
Last position:
Managing Director at ESIS-ERP GmbH
- Took over management of the company
Knud W.
Last position:
Lead Programmer, Architect and Deputy Product Owner at Bundesagentur für Arbeit
- Lead programmer, architect and deputy product owner
- Completed transition from zPDV to STEP
- Ensured quality of C++ and Perl sources through automated and manual checks
- Supported resolution of incidents and errors in testing
- Implemented batch for supplementary assignment of payment run numbers
- Implemented batch for distribution of SGB 2 information to the central payment unit
- Supported replacement of Solaris with Linux
- Upgraded gcc from 7.4 to 9.3
- Programmatically generated Makefiles from Borland projects for builds
- Extended funding data with new attribute “internship travel cost indicator”
- Programmatically generated XSD and WSDL files from IDL definitions
- Represented the product owner when needed
- Implemented batch for one-time payment processing
- Developed generator for Liquibase files
- Implemented and maintained regular anonymization of production data
- Supported migration from SLES 12 to SLES 15
- Supported introduction of mutual TLS
- Implemented batch for sending deletion impulses to EDA BE
- Organized script directory structure
- Investigated potential introduction of String-Latin and implemented minimal solution
- Remediated security findings identified by CheckMarx
- Supported PAP recalculations and general change notices
- Converted ERP interfaces from SOAP to REST
- Planned technical and business topics such as register modernization, cash register security, training costs, four-eyes principle
Jan B.
Last position:
API-Engineer at Freelance
- API-first product design (OpenAPI 3, HAL) and development (NodeJS)
- Setting up DevOps pipelines with GitHub Actions in an AWS architecture
- Technologies: OpenAPI 3, REST, HAL, NodeJS, JavaScript, TypeScript, AWS, AWS Lambda, Docker, GitHub Actions
Sebastián K.
Last position:
Smart Charging at Mercedes-Benz, MBTI
Agile software development in an interdisciplinary environment
Cross-team collaboration to achieve important milestones
Independently developing new and improving existing features
Estimation, refinement, implementation, and presentation
Finding solution ideas, analyzing problems, rolling out bug fixes
Writing automated tests, manual testing, log and error analysis
Ensuring high availability, fault tolerance, and scalability of the production environment
Rolling out releases and multi-stage infrastructure
Setting up alerts and monitoring
Pair programming, code reviews, documentation
On-call duty, 3rd level support
Event-Driven Architecture, Clean Code, Hexagonal Architecture
Microservices based on Go (Gin), Java 21 (Spring Boot 3), Python (FastAPI)
Terraform/OpenTofu, KQL, SQL, JSON, REST, Helm, ArgoCD, AzureCLI, K9s, OAuth2
Postgres, Redis, Kafka, Azure EventHub, Kubernetes, nginx, Ingress
AppInsights, LogAnalytics, OpenTelemetry, Datadog, OpenAPI 3, Swagger
Azure DataExplorer, Storage, KeyVault, Container Registry, Azure Functions,…
Junit5/Jupiter, testify, RestAssured, Docker Compose, Wiremock
IntelliJ, Scrum, Kanban, Teams, Confluence, OpsGenie, Arc42
GitHub CI/CD, GitLab CI/CD, Azure DevOps
EV charging protocols (EVSE, OCPP, V1G, V2G)
Linus H.
Last position:
Software Developer at Check24 Vergleichsportalreise Reise Gmbh
- Designing, developing, and maintaining web portals, including creating and connecting interfaces to other systems (APIs)
- Performing error analysis and troubleshooting
- Designing and implementing data structures
- Refactoring software components to improve maintainability
- Creating user interfaces
- Web portal for monitoring error messages (PHP, MySQL, Elasticsearch, ExtJS 5.0, Symfony)
- Web portal for electric car buying advice, further development, and providing a white-label solution for a startup in the e-mobility sector (PHP, Symfony, JavaScript, Bootstrap 5)
- Providing a REST API for a healthcare app (PHP, Symfony API Platform, AWS)
- Developing middleware for data exchange between multiple applications (PHP)
Discover over 15,000 top freelancers
Statistics of experts using REST API
Aggregated from the professional profiles of matched freelancers.
Experience
19 years (Germany: 17 years)
Position duration
2.4 years (Germany: 2.9 years)
Positions per freelancer
11 (Germany: 12)
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Retail, Healthcare
Certification focus areas
Project Management, Operations, Product Development
Bachelor's degree or higher
82% (Germany: 92%)
Master's degree or higher
55%
Certifications per freelancer
1 (Germany: 3)
Most common languages
German, English, Spanish
Speak two or more languages
93% (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 Leipzig 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 Leipzig 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 19 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
REST API 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 (93%)
- Retail (50%)
- Healthcare (43%)
- Professional Services (43%)
- Tourism (43%)
- Automotive (29%)
- Energy (29%)
- Manufacturing (29%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What REST APIs do
A REST API is a web interface that lets software exchange data through HTTP. It represents resources such as users, orders or documents and commonly uses JSON responses. RESTful APIs support web applications, mobile apps, partner integrations and internal services.
Core design work
Strong REST API specialists define clear resources, endpoints, request methods and response formats. They handle status codes, pagination, filtering, versioning and consistent error messages. Good design keeps an interface understandable for consumers and stable as the product evolves.
Ecosystem and tooling
REST API work connects application code with a broad delivery toolchain:
- OpenAPI or Swagger specifications for contract documentation
- OAuth 2.0, JWT and API keys for access control
- Postman, Insomnia and automated integration tests
- API gateways, rate limits, logs and monitoring
Common implementations use Java, Spring Boot, .NET, Node.js, Python, Go or PHP. Database design, cloud services and CI/CD practices often shape the API as much as the endpoint code.
When companies need help
Companies bring in freelance REST API experts when a new product needs a dependable integration layer, when a legacy interface is difficult to maintain or when partner access must be introduced safely. In Leipzig, specialists may support local product teams on site or work remotely with distributed teams. Clear English and, where needed, German communication helps keep requirements and API contracts aligned.
Typical project deliverables
A REST API engagement can cover discovery, interface design, implementation and long-term improvement:
- OpenAPI documentation and a consistent resource model
- Authentication, authorization and input validation
- Connectors for payment, CRM, ERP or logistics systems
- Contract, integration, performance and security tests
- Migration plans for version changes or legacy endpoints
The right scope depends on the system boundaries, data sensitivity and number of consuming applications.
What strong experts bring
Experienced REST API professionals think beyond individual endpoints. They make trade-offs between REST and alternatives such as GraphQL or SOAP, protect sensitive data, and design for observability and failure recovery. They also explain decisions clearly, maintain useful documentation and test real consumer workflows. Review examples should show stable contracts, secure defaults and practical collaboration with product, frontend and backend teams.
Frequently asked questions
Before you brief your next project: the most common questions about REST API.
A REST API allows separate software systems to communicate over HTTP. Companies use it to connect web and mobile applications with databases, SaaS products, payment services, CRM systems and internal business processes.
A REST API usually exposes resources through predictable URLs and HTTP methods, which makes it widely understood and easy to integrate. GraphQL gives clients more control over returned data, while SOAP provides stricter message standards and is still relevant in some enterprise environments.
A strong REST API specialist should understand HTTP, data modeling, SQL or NoSQL databases, authentication and automated testing. Experience with OpenAPI, API gateways, cloud infrastructure, observability and CI/CD is also valuable for production work.
A REST API project may suit a focused specialist when the scope is clear and the system is simple. Complex integrations call for proven experience with distributed systems, security, versioning, high availability and the business domain involved.
Yes. REST API work is well suited to remote collaboration because specifications, code reviews, tests and documentation can be shared digitally. On-site sessions in Leipzig can still help when requirements are unclear or several local teams need to agree on service boundaries.
Review whether the REST API has clear resource naming, consistent status codes, useful documentation and predictable error handling. Ask for examples of contract tests, authentication decisions, monitoring and how breaking changes were managed.
An OpenAPI specification should describe endpoints, parameters, request and response schemas, authentication, status codes and error formats. It gives product, frontend and backend teams a shared contract and can support documentation, validation and test generation.
Yes. A REST API specialist can map current consumers, identify inconsistent endpoints, add tests and introduce a safer versioning or migration approach. The work should protect existing integrations while making future changes easier to document and release.
The average hourly rate of freelancers in Leipzig, Germany who have used REST API in their recent projects is 90 €, which corresponds to a daily rate of about 716 € based on an 8-hour working day.
Of the freelancers in Leipzig, Germany who have used REST API in their recent projects, 82% hold at least a Bachelor's degree and 55% hold at least a Master's degree.
On average, freelancers in Leipzig, Germany who have used REST API in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 2.4 years.
The most common languages among freelancers in Leipzig, Germany who have used REST API in their recent projects are German (93%), English (93%), and Spanish (14%).
The most common industries among freelancers in Leipzig, Germany who have used REST API in their recent projects are Information Technology (93%), Retail (50%), and Healthcare (43%).
The most common business areas among freelancers in Leipzig, Germany who have used REST API in their recent projects are Information Technology (100%), Product Development (100%), and Quality Assurance (57%).
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.
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Hamburg 
Munich 
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Frankfurt 
Stuttgart 
Dusseldorf 
Dortmund 
Essen 
Bremen 
Dresden 
Hanover 
Nuremberg Request a free demo
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