REST API Experts in Hamburg
matched in minutes from over 15,000 CVs with the power of AIHire experts who design resource-based interfaces, secure endpoints and integrate REST APIs with web, mobile and cloud systems. FRATCH connects you quickly and precisely with vetted, available freelancers who fit your technical needs.
Meet FRATCH Experts in Hamburg, who have recently used REST API
Yashar S.
Last position:
Compliance Consultant at RAS Reinhardt Maschinenbau GmbH
- Designed and moderated a NIS2 preparation workshop for RAS Reinhardt Maschinenbau GmbH and its IT service provider Catuno GmbH. Together with executive management and IT leadership, the current status was assessed, an initial GAP analysis was conducted and areas for action were prioritized based on ISO 27001.
- Developed an ISO-27001-based regulatory framework (ISMS) for NIS2 compliance, including a structured current/target GAP analysis, targeted improvement of the security maturity level and preparation of the organization for NIS2 audit readiness.
Niko S.
Last position:
Developing Architect, Technical Lead "gridlytics" at HH Energienetze
- Building a data integration platform for high, medium, and low voltage assets for contextual analysis of time series with master data from the SCADA control system (IEC 60870 104), INIS, and SAP.
- Responsibility for the architecture and implementation of the solution, as well as sparring partner for the Product Owner.
- Use of Kotlin, Spring Boot, Maven, TimescaleDB, PostgreSQL, liquibase, Elements IoT, Docker, Kubernetes, Grafana, Python, jupyter, and various API gateways.
Daniel S.
Last position:
Senior Software Engineer at energielenker solutions GmbH
- Designed and implemented a Python-based ETL pipeline with the Dagster framework to transform raw energy data from heterogeneous sources using InfluxDB and visualizations in Grafana
- Defined time-based and dependency-based jobs
- Deployed to managed Kubernetes clusters using Helm
- Integrated InfluxDB Cloud
- Prepared data for use in Grafana, including cleaning, normalization, and time-based resampling in Python
- Developed dashboards and visualizations in Grafana
- Developed unit tests with mocking using pytest
- Set up a CI/CD pipeline in GitLab
Technologies: Python, Dagster, InfluxDB, Grafana, pandas, pytest, REST, CI/CD, GitLab, Container, Kubernetes, Helm, Docker, Cloud
Cornelius H.
Last position:
Solution Architect at STIHL
- Remodeling of the system architecture for an Azure-based platform aimed at rapid development of new functionalities
- Modeling of a staging concept for the fulfillment of diverse customer and QA needs
- Creation of requirements for, and oversight of, a proof-of-concept supplier project for a Flutter app with highly advanced BLE functionalities
- Comparison of multiple observability platforms for feasibility and requirements fit within the project environment
- Creation of a mobile app architecture based on domain-driven architecture
- Position of technical advisor and accountable solution architect for two development teams
- Execution of architecture reviews and alignment of changes with architectural expectations
- Skills & Technologies: Microsoft Azure , App Services, NodeJS Mono-repository, microservice architecture, domain driven design, self contained systems, requirements engineering, CI/CD, DevOps, API design, solution architecture
Heena P.
Last position:
Retirement Spend & Tax Optimizer Agentic AI App (Vibe Coding) at Personal Project
Self-directed exploration of agentic AI development methods, taken from idea to a working, publicly usable application
- Built an interactive planning tool for modelling retirement withdrawals and tax strategy using an agentic AI (vibe coding) development approach – demonstrating self-directed investigation of new AI-assisted development methods
- Delivered live, tax-aware spending projections and adjustable user inputs; shipped as a free, install-free browser application built in Python, with attention to usability for non-technical users
Rizwan B.
Last position:
Software Developer/Database/Devops at Sutor Bank
Project:
- Migration of existing VB6 applications to C# (Web API, web app)
- Report development and risk management systems (C#, API interfaces, databases)
- Document archive (API interfaces, databases)
Team size: 9 people
- Reports for Risk and Credit Management Development and maintenance of report structures to support risk and credit decisions, including data modeling, validation, and automated delivery for business departments.
- Migration and maintenance of a legacy system to the latest version of .NET for the asset management system Planning and execution of the modernization of an existing asset management system, including code refactoring, performance optimization, test automation, and sustainable maintenance after migration.
- Replacement of the COM-based archive connection with a REST API Redevelopment of the connection of the document archive (HYPARCHIV) to a REST API based on OpenAPI/Swagger, including archiving with index and stamp fields as well as PDF export into the customer portal.
- Redesign of payment receipt processing Replacement of an existing Oracle PL/SQL process with a new implementation in C# based on a business concept, including business alignment, data modeling, and test coverage.
- Design and implementation of tests, creation of deployment pipelines, and documentation
- Further development and implementation of change requests.
- Regular code reviews within the team as well as optimization of application scalability and stability
Technologies: C#, .NET 10, ASP.NET, Unit of Work, IoC, Three-Tier Architecture, Entity Framework Core, DB First, Web API, Swagger, OpenAPI, Python, Oracle, HYPARCHIV, Azure, PowerBI, DevOps, AKS (Azure Kubernetes Service), GIT, xUnit, NSubstitute, TypeScript, Vue.js, Pinia,
Methods: agile development using Scrum
Florian W.
Last position:
Software Engineer at micimo GmbH
- Developing a professional scheduler for organizations with specific detailed requirements
- Evaluating different existing software solutions
- Creating a list of technical requirements
- Implementing these requirements
- Selected technologies: WebDAV, CalDAV, Rust, Baikal, OAuth, Keycloak
Klaus-Dieter P.
Last position:
IT Architect at REWE digital
- Development and further development of e-invoicing solutions, interfaces for invoice processing, and implementation of regulatory requirements
Technology & methods: XRechnung, ZUGFeRD, EN 16931, XML, API integration, backend development, cloud services, automation, compliance, AI-supported document analysis
Rainer D.
Last position:
Enterprise Architecture Management / Backend Software Developer at Polizei Hamburg
- Several projects in a police context
- Model and document police procedures/projects with Archimate (as-is/to-be) in the context of P20 (BKA)
- Create software architectures with microservices
- POC development with Springboot/Docker/Kubernetes
- Project size: 10 people
- Enterprise architecture management with Togaf and Archimate
- Backend software development Springboot
- DevOps with Kubernetes
- Implemented using: Java 17/21, Springboot 3, P20 architecture, Togaf, Archimate
Alex O.
Last position:
Contractor at Telefonica Germany GmbH & Co. OHG
- Data-analysis, Preparation, gathering and coordination of business requirements for retrieval of monthly- and long term (CLV – relevant) cost- and revenue-components per contract for a customer–base–grouping project (HUB–Project) for B2C-Postpaid-Controlling
- Concept and Implementation of cost- and revenue-KPIs calculation and corresponding CLV–reports (Oracle, Perl, SVN, MS SQL Server, MS Power BI, Serviceware Performance Analytics)
- Operational support of the HUB-Project – various ad-hoc reports, deployments, job-scheduling etc. (Oracle, SVN, BICSuite–Scheduler, DWSODA etc.)
- Analysis, implementation, retrieval and reporting of various physical and financial KPIs for B2P-Prepaid Business on an existing data-mart (Oracle, Perl)
Marian G.
Last position:
Senior Software Engineer at B&P Bergmannpartners
- Full-stack development of a customizable SaaS platform for the real estate industry
- Running domain discovery processes to gather business requirements and derive technical specifications
- Designing and implementing core features based on a Remix MVC architecture with TypeScript, Node.js, and PostgreSQL
- Focus on usability, extensibility, and high scalability of the platform
Guido B.
Last position:
Independent Management Consultant and Interim Manager at BCTC Unternehmensberatung Guido Bäcker
Consulting, training, and coaching in the financial sector on strategy, organization, and IT topics
MorgenFund: Advising the operator of a fund platform on software selection for a sub-ledger "Cash Accounts" based on Virtual IBANs (VIBAN)
Structuring requirements, market screening, creating RfIs, communicating with vendors, and conducting the selection process
UniCredit/HypoVereinsbank: Workstream lead "Booking and Customer Reporting" in the payment transformation project "PULS"
Business analysis, creating business requirements and aligning solution items as part of the functional specification with the bank's IT service providers
Business analysis of SEPA CT and SWIFT MX (.camt, .pain, and .pacs formats), change management, team lead for a virtual team of fifteen line experts, and stakeholder management
equensWorldline Germany: Program management for three projects of the SWIFT service bureau (CBPR+, ESMIG, and Euro1Step1 migration) as part of the SWIFT MX migration
Managing individual project managers regarding overarching goals and requirements; reporting to internal and external committees and stakeholders; coordinating with dependent projects and programs
Project management/PMO: interim project management, stand-in for project managers, resource planning, budget and cost management, general PMO tasks
Torsten L.
Last position:
Technical design and development of frontend and backend for e-waste-race.de / textil-race.de at Das macht Schule gemeinnützige GmbH
- Creation of a platform where schools can run competitions to collect e-waste or old textiles
- Development of a shared PHP backend for administration by the client
- Connection of two separate WordPress sites via REST API
- Development of a custom WordPress theme with an extensive login area for students
- Setup of normally editable content pages using Elementor
Anastasiia K.
Last position:
Senior Test Automation Engineer at E.ON
- Reviewing functional and technical requirements from a testing perspective
- Creating test cases and automated tests to validate requirements
- Performing manual and automated functional, end-to-end, and regression tests
- Documenting test results and tracking defects
- Using models like GPT-4, BERT, and Hugging Face Transformers for automated test case generation, analysis of test results, and improving test coverage, including bias checks and security reviews
- Techs: MS Office, Jira, Zephyr, Confluence, Tosca, stakeholder communication, Agile, Kanban, Scrum, OpenAI API, Hugging Face, PyTorch, LangChain.
Holger G.
Last position:
Test Automation Engineer, Quality Assurance Consultant at T-Systems
- Poliks – State Police System for information, communication, and case management and other state variants (ViVa, Bravo, customs)
- Developed a test framework for test automation to replace an existing proprietary test client for new developments, focusing on easy maintenance and simple extensibility for new technologies
- Designed the architecture
- Implemented the architecture
- Created a proof of concept by migrating existing test cases into the new test framework
- Platform: C#, .NET, Jira, XRay, Confluence, Playwright, Selenium, UI Automation, Appium, HTML, Git, VMWare, Windows 11, Linux
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 years (Germany: 2.9 years)
Positions per freelancer
14 (Germany: 12)
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Retail, Banking and Finance
Certification focus areas
Information Technology, Product Development, Project Management
Bachelor's degree or higher
83% (Germany: 92%)
Master's degree or higher
48% (Germany: 55%)
Doctorate
12% (Germany: 7%)
Certifications per freelancer
2 (Germany: 3)
Most common languages
German, English, French
Speak two or more languages
98% (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 Hamburg 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 Hamburg 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 (94%)
- Retail (57%)
- Banking and Finance (50%)
- Professional Services (46%)
- Media and Entertainment (37%)
- Manufacturing (35%)
- Healthcare (33%)
- Energy (31%)
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 resources through standard HTTP methods such as GET, POST, PUT and DELETE. RESTful APIs commonly return JSON and connect browsers, mobile apps, SaaS products, internal services and external partners. Their stateless design supports clear ownership and independent system changes.
Where they are used
REST API projects appear wherever separate systems need dependable data exchange. Typical deliverables include:
- Public APIs for customer and partner access
- Backend interfaces for web and mobile applications
- Integrations with payments, CRM and ERP systems
- Microservice communication and service gateways
- Reporting, identity and data synchronisation endpoints
Ecosystem and tooling
Strong specialists work across API design, implementation and operation. Their toolkit may include OpenAPI or Swagger for contracts, Postman for testing, OAuth 2.0 and JWT for access control, and API gateways for routing and policy enforcement. They also use JSON Schema, Git, CI/CD pipelines, Docker and cloud observability tools where the surrounding system requires them.
When companies need support
Companies bring in freelance REST API expertise when an integration is unreliable, an API needs to be opened to partners or a legacy interface must be replaced without disrupting users. Specialists can define resource models, document contracts, improve error handling and establish versioning rules. In Hamburg, this can support local commerce, logistics, media and industrial systems while allowing remote collaboration across distributed teams.
What good delivery includes
Experienced professionals treat an API as a product, not only as a set of routes. They clarify naming, status codes, pagination, filtering, idempotency and backward compatibility before implementation. They create meaningful documentation, automated tests and monitoring so consumers can understand failures and teams can change the service safely.
How to assess specialists
Look for professionals who can explain design decisions in terms of consumers, data ownership and operational risk. Ask for examples of API contracts, authentication flows, integration tests and migration plans rather than only framework knowledge. The right specialist communicates clearly in English and, for Hamburg-based collaboration, can align effectively with the team’s expected on-site or remote working style.
Frequently asked questions
Curious about REST API? Here are the answers that come up again and again.
A REST API allows separate applications to exchange resources over HTTP. Companies use it for web and mobile backends, partner integrations, internal services, payments, identity workflows and data synchronisation.
A REST API exposes resource-oriented endpoints and usually relies on established HTTP semantics, which makes it straightforward to document and integrate. GraphQL lets consumers shape responses more precisely, while SOAP provides stricter message standards and is still relevant in some enterprise environments.
A strong REST API specialist should understand HTTP, JSON, database design, authentication and automated testing. Useful adjacent skills include OpenAPI, OAuth 2.0, API gateways, cloud deployment, observability and at least one backend programming ecosystem.
The need depends on the system’s risk, traffic, integrations and compatibility requirements. A REST API project with a small internal scope may suit a specialist with focused delivery experience, while public or business-critical interfaces call for someone who has handled versioning, security, monitoring and migrations.
Yes, REST API work is well suited to remote collaboration because contracts, documentation, tests and code can be reviewed online. Hamburg-based teams should agree on communication routines, working hours, access controls and whether occasional on-site workshops are needed.
Review whether the REST API has consistent resource naming, suitable HTTP status codes, clear error responses and complete documentation. Also examine automated tests, authentication design, observability, backward compatibility and how easily an external consumer can use the contract.
In everyday project language, REST API and RESTful API usually refer to the same style of HTTP interface. Strictly speaking, REST describes architectural constraints, and an interface is more fully RESTful when it follows those constraints consistently rather than merely returning JSON over HTTP.
Before taking on a REST API assignment, clarify the consumers, resource model, authentication method, data ownership, performance expectations and release process. Also confirm who maintains the documentation, how breaking changes are handled and which environments and logs are available.
The average hourly rate of freelancers in Hamburg, Germany who have used REST API in their recent projects is 96 €, which corresponds to a daily rate of about 768 € based on an 8-hour working day.
Of the freelancers in Hamburg, Germany who have used REST API in their recent projects, 83% hold at least a Bachelor's degree, 48% hold at least a Master's degree, and 12% hold a doctorate.
On average, freelancers in Hamburg, Germany who have used REST API in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 2 years.
The most common languages among freelancers in Hamburg, Germany who have used REST API in their recent projects are German (100%), English (98%), and French (15%).
The most common industries among freelancers in Hamburg, Germany who have used REST API in their recent projects are Information Technology (94%), Retail (57%), and Banking and Finance (50%).
The most common business areas among freelancers in Hamburg, Germany who have used REST API in their recent projects are Information Technology (96%), Product Development (94%), and Quality Assurance (59%).
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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