REST API Experts in Vienna
matched in minutes by AIHire experts who design resource-based interfaces, integrate business systems and secure API services, with precise matching to vetted, available freelancers for fast delivery.
Meet FRATCH Experts in Vienna, who have recently used REST API
Chrisabel P.
Last position:
AI Systems & Product Strategy Expert at Webmeisterin
I build. I advise. I think in systems. After years leading digital transformation at scale — Accenture, BP, Lidl — I made a deliberate choice: trade platform dependency for structural independence. My focus is at the intersection of AI systems, product strategy, and venture thinking. I work with operators and founders who want to move fast without losing control — of their data, their stack, their direction.
Roman M.
Last position:
Software Engineer at FSM Rechtsanwälte
- Develop AWS-based components connecting Python backend services to React/TypeScript frontends.
- Improve database queries and application workflows for document processing and screening.
- Evaluate LLM retrieval and document-review workflows as part of the product stack.
Michael L.
Last position:
IAM Developer & IT Architect at Internationale Bank
Design and implementation of new functionalities in the areas of Lifecycle Management (LCM), Role Management (RLM) and Access Governance
Adjustment of the company-wide Segregation of Duties (SoD) matrix to ensure regulatory and internal compliance requirements
Further development and configuration of recertification processes
Creation and adaptation of custom workflows, rules and tasks in SailPoint IdentityIQ (BeanShell, XML, Java)
Use of static code analysis with SonarQube to ensure code quality and compliance with defined development standards
Regular code reviews within the development team to ensure quality, share knowledge and follow clean code principles
Work in an agile Scrum team with daily communication, sprint planning and reviews
Coordination with testers, test managers and business departments to ensure quality and smooth production rollout
Active involvement in release planning and deployment coordination, including test preparation, cutover activities and rollback strategies
Analysis and sustainable resolution of issues in the IAM production environment (2nd- and 3rd-level support)
Reproduction of complex errors, identification of root causes and implementation of lasting fixes
Creation of technical analyses and recommendations for operations and further development
Marcel S.
Last position:
Senior AI Engineer - Python at Insurance Company
Project Tech Stack: Python, AWS, Azure, FastAPI, openai, pandas, unittest/pymock
Achievements:
- Engineered automated data extraction pipelines to transform complex Excel datasets into structured formats via LLM-driven workflows.
- Architected a generative slide-deck engine that translates natural language prompts into formatted presentation assets.
- Integrated advanced LLM capabilities with the OpenAI Response API, implementing sophisticated tool-calling and structured output logic.
- Developed and containerized scalable backend microservice using FastAPI, Docker, and OpenShift to host and serve agentic skills.
Jörg P.
Last position:
Process Manager (70%) / Business Analyst (30%) at T-Mobile Austria GmbH (Magenta)
- BSS system implementation for B2B / transformation of the central B2B system landscape
- End-to-end business responsibility for defining, structuring and prioritizing key B2B business processes as part of a complex BSS transformation.
- Work in an agile, SAFe-like setup with multiple teams involved, along with regular coordination with business, IT, solution design and architecture.
- Translation of business requirements into implementable epics, features, user stories, process models and acceptance criteria as the basis for technical implementation.
- Close collaboration with solution design and architecture to assess technical dependencies, interfaces, data flows and system impacts.
- Management of target process design as the basis for implementation in Infonova BSS.
- Interface management between business departments, IT, architecture, development and operational units, including facilitation of cross-functional workshops.
- Ensuring process consistency, governance, decision-making capability and business acceptance as part of the system implementation.
Michail M.
Last position:
OpenShift Specialist, Developer at Insurance
Project goal: Introduce OpenShift as the run-time platform and migrate all applications to OpenShift.
My contribution: Make sure logging and monitoring for the applications were in place. Set up and put into operation the OpenShift components for logging and monitoring (Elasticsearch, Prometheus, and Grafana). Develop and implement the security concept for OpenShift. Work with developers to define and carry out the application changes needed for the OpenShift migration. Integrate monitoring into the applications.
Technical environment: Java, WebSphere Liberty, OpenShift components, Elasticsearch (ELK stack), Prometheus, Grafana.
Markus K.
Last position:
Document Development at Insurance Company
- Replacement of original Dopix documents and modules into the Quadient document environment
- Extension of document logic
Joseph W.
Last position:
Freelancer Cloud / Solution Architect (AWS) at A1 Bank
- I am responsible for providing solution architecture and technical assistance for a migration initiative aimed at transitioning to a new core banking system.
- The project involves replacing in-house development with a commercially available off-the-shelf core banking system operated as SaaS on AWS.
- Duties encompass solution design, technical coordination, supporting development teams, and providing IT support and troubleshooting.
- Managing over 10 global vendors and partners is crucial to project success.
- Technologies: VMWare ESXi, AWS, EKS Kubernetes, Mastercard Payment Transaction Service, Avaloq, A1 Telekom Austria infrastructure, CheckPoint FW, F5, Site-to-Site VPNs, PingID, Futurae SDK, Airlock, UC4/Automic, Firebase, iOS/Android lifecycle management, AWS IAM, AWS AppStream, AWS S3, AWS Transfer Family, QlikView, OpenAPI.
Michael P.
Last position:
Strategy Consultant & Program Architect at Hypo Tirol Bank AG
- Portfolio Analysis & Migration Roadmap: Conducted structured analysis and risk classification of the HCL Notes infrastructure, created a prioritized migration portfolio with effort estimates as a key decision basis for management.
- Target Architecture & Modernization Concept: Developed the architecture strategy for retiring legacy applications, defined requirements for a centralized business process engine to reduce OPEX and licensing costs in the long term.
- Program Governance & Setup: Established roadmap and backlog structures as well as central project documentation (MS SharePoint), set up stakeholder management for the Notes decommissioning program.
Vladislav F.
Last position:
Senior Test Automation Engineer / Test Manager at Stadt Wien – WUKSEA
- Creating test scenarios, manual test cases and test data using boundary value analysis and equivalence classes
- Executing functional and non-functional tests (manually with Postman and web application, automated with WebDriver, JUnit and NUnit)
- Setting up, automating and maintaining the test automation framework with Java, Spring Boot, Selenium and Cucumber in IntelliJ (system, regression, smoke, UI and integration tests for web front-end and SOAP API backend interfaces)
- Automating backend NUnit test cases in Visual Studio
- Test management: developing and implementing test strategy and test plans, controlling tests, quality ownership and prioritizing risk-based tests, as well as maintaining documentation in Confluence
- Detailed analysis and quality assurance of requirements
- Creating and maintaining Jenkins pipelines, ensuring quality in build & deployment
- Close collaboration with business analysts, developers, testers and test management
- Identifying, creating and tracking defects/bugs, with thorough test documentation
- Reporting test results and defect reports
- Monitoring test processes and continuous improvements
- Reviewing test data and test results in PostgreSQL database via pgAdmin
- Supporting effort estimation and backlog prioritization
- Analyzing and debugging development code System environment: Java, JUnit, Spring Boot, Selenium, Cucumber, JavaScript, Jenkins, C#, NUnit, Postman, Bitbucket, Confluence, Jira, xRay, pgAdmin, PostgreSQL, SonarQube, Maven, IntelliJ, Visual Studio, CI/CD, SOAP API interfaces
Maximilian G.
Last position:
Solo Developer / Founder at InvAPI
- Privacy-first, stateless e-invoice API providing AI-powered extraction, bidirectional format conversion (UBL/CII/ZUGFeRD), batch processing, and validation for German/Austrian e-invoice compliance
- Technologies: Nuxt 4, Vue 3, Nitro, TypeScript, Cloudflare (D1, R2), Stripe, OAuth, AI/LLM integration
Attila D.
Last position:
Full-Stack Software Engineer at Research Data Evaluation
- Custom anonymized research data analyzer, providing insights and facilitating data-driven decision-making.
- Designed and developed back- and frontend.
- Delivered end-to-end solution.
- Accelerated research timeline by 2 months.
Nedim K.
Last position:
Manual Tester and Test Automation Engineer at IT-Systemhaus der Bundesagentur für Arbeit
- Design appropriate test cases to verify the GUI in Azure Test Plans
- Creation and execution of manual test cases
- Test design for user stories to be implemented in the current sprint
- Analysis of deviations/bugs based on log files and Kibana dashboards
- Creation of bug tickets with error description, screenshots, and short videos
- Prioritization of open bug tickets together with the PO
- Retest of bugs and hotfixes
- Execution of manual tests to ensure a 100% fulfillment rate of all functional requirements
- Selection, installation, and maintenance of a test automation tool (Selenium)
- Implementation of automated regression tests
- Continuous expansion of the object repository and adaptation of automated test cases (acceptance, integration, and system tests)
- Creation of test logs before each sprint change
Damian G.
Last position:
Senior Test Manager Release Management at SVS
- Proof of Concept Test Management Tool
- Test strategy
- Test concepts
- Management of requirements
- JIRA
- Zephyr
- Confluence
- MS Word
- MS Project
- MS Excel
- Tosca
Jori M.
Last position:
Agile IT Manager Healthcare Systems at MA01 Gov. Digital City
- Responsible for managing GMP-critical systems
- Leading a team of 20 professionals
- Vendor management with a €15M annual budget
Discover over 15,000 top freelancers
Statistics of experts using REST API
Aggregated from the professional profiles of matched freelancers.
Experience
19 years
Position duration
1.7 years
Positions per freelancer
11
Top business areas
Information Technology, Product Development, Project Management
Top industries
Information Technology, Banking and Finance, Government and Administration
Certification focus areas
Information Technology, Project Management, Product Development
Bachelor's degree or higher
81%
Master's degree or higher
56%
Certifications per freelancer
3
Most common languages
German, English, Russian
Speak two or more languages
100%
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 Vienna 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 Vienna 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%)
- Banking and Finance (67%)
- Government and Administration (61%)
- Transportation (44%)
- Telecommunication (44%)
- Insurance (39%)
- Healthcare (33%)
- Professional Services (33%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What REST APIs do
REST APIs connect software through clear HTTP requests and responses. They expose resources such as customers, orders, payments or documents so web applications, mobile apps and external services can use them. A well-designed RESTful API keeps clients and backend systems loosely coupled.
Core design work
Experts define resource models, endpoint structures, request formats and response contracts. They choose suitable HTTP methods, status codes, pagination, filtering and error responses. They also document behavior with OpenAPI so internal teams and integration partners can use the service consistently.
Ecosystem and tooling
REST API work commonly spans backend frameworks, databases, identity services and cloud infrastructure. Strong specialists are comfortable with:
- OpenAPI and Swagger documentation
- OAuth 2.0, JWT and role-based access
- JSON schemas, validation and versioning
- Postman, automated tests and CI pipelines
- API gateways, logs and observability
Where companies use them
Companies bring in REST API expertise to connect products, modernize legacy interfaces or expose selected business capabilities to partners. Typical assignments include:
- Mobile and web application backends
- E-commerce, payment and order integrations
- CRM, ERP and third-party system connections
- Public partner APIs and internal service interfaces
- Migration from tightly coupled or undocumented endpoints
When freelance expertise helps
Freelance professionals are useful when an API must launch quickly without compromising its contract or security. They can audit an existing interface, establish standards across several teams, or take ownership of integration work during a product transition. In Vienna, collaboration may combine remote delivery with on-site workshops, depending on the project and language needs.
What strong professionals deliver
The best specialists think beyond endpoint implementation. They clarify business resources, handle compatibility, protect sensitive data and test failure paths as carefully as successful requests. Look for clear API documentation, thoughtful naming, reliable automated tests and evidence of integrations that remain maintainable as clients evolve.
Frequently asked questions
Quick answers to the questions that come up most around REST API.
A REST API lets applications exchange data and trigger actions through standard HTTP requests. Companies use RESTful APIs for web and mobile backends, partner integrations, internal services and connections between business systems.
REST API design uses resource-oriented endpoints and standard HTTP behavior, which makes it familiar and broadly supported. GraphQL gives clients more control over returned data, while SOAP provides stricter messaging and contract conventions; the right choice depends on integration constraints, governance and client needs.
A strong REST API specialist usually understands backend programming, databases, authentication and cloud deployment. Useful adjacent skills include OpenAPI, API gateways, automated testing, monitoring, OAuth 2.0 and secure handling of personal or financial data.
The right level depends on the API’s risk, traffic, integrations and lifecycle expectations. A straightforward internal interface may need focused implementation skills, while a public or regulated REST API calls for experience with versioning, security, observability and backward compatibility.
Yes, REST API work is often well suited to remote collaboration because specifications, repositories, tests and documentation can be reviewed online. Vienna-based companies may still prefer on-site workshops for domain discovery, team alignment or sensitive integration planning, with English or German depending on the stakeholders.
Ask for examples of REST API contracts, documentation and tests, then discuss the decisions behind them. Quality shows in consistent resource modeling, useful error handling, secure authentication, clear versioning and the ability to explain trade-offs to both technical and business teams.
A REST API engagement may produce endpoint designs, OpenAPI specifications, implementation code, automated tests and deployment configuration. It should also include authentication rules, error conventions, example requests, monitoring guidance and documentation that another team can maintain.
Bring in a REST API expert when integrations are failing, endpoint behavior is inconsistent or a new product needs a dependable service contract. Specialist help is also valuable before a public launch, during legacy modernization or when several teams need shared API standards.
The average hourly rate of freelancers in Vienna, Austria who have used REST API in their recent projects is 93 €, which corresponds to a daily rate of about 742 € based on an 8-hour working day.
Of the freelancers in Vienna, Austria who have used REST API in their recent projects, 81% hold at least a Bachelor's degree and 56% hold at least a Master's degree.
On average, freelancers in Vienna, Austria who have used REST API in their recent projects have 19 years of professional experience, with a single engagement typically lasting around 1.7 years.
The most common languages among freelancers in Vienna, Austria who have used REST API in their recent projects are German (100%), English (100%), and Russian (22%).
The most common industries among freelancers in Vienna, Austria who have used REST API in their recent projects are Information Technology (94%), Banking and Finance (67%), and Government and Administration (61%).
The most common business areas among freelancers in Vienna, Austria who have used REST API in their recent projects are Information Technology (100%), Product Development (89%), and Project Management (61%).
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.
Countries:
Vienna 
Graz Request a free demo
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