JSON Expert in Vienna
for reliable data exchange, matched in minutes with vetted and available freelancersHire experts who design clear data structures, validate API payloads and connect JSON with REST services, JavaScript applications and cloud systems. FRATCH matches you quickly and precisely with vetted, available freelancers.
Meet FRATCH Experts in Vienna, who have recently used JSON
Matthias K.
Last position:
Requirements Engineer & Business Analyst at Media Company
Analysis of existing work, information and decision-making processes.
Identification and prioritization of suitable use cases for AI agents.
Elicitation of functional and non-functional requirements.
Design of collaboration between users and AI agents, including control and escalation mechanisms.
Support for the implementation of the AI agents and adapted keyboard hardware.
Business target vision for the AI-first transformation.
Structured and prioritized requirements for implementation.
Defined roles, interactions and control points between people and AI agents.
Preparation for the gradual automation of productive work processes.
Techstack: AI agents, LLMs, agent orchestration, RAG, APIs, automation, hardware
Thomas P.
Last position:
Change Manager / Sales Transformation at SEFE
- Organizational Change Management as part of a group-wide, supranational sales transformation, serving as the core of a broad restructuring of business-critical areas, with end-to-end control of the change process and long-term embedding and securing the future readiness of sales.
- Initiation and end-to-end steering of the sales transformation program, including in-depth analysis to identify, assess, and strategically involve all relevant stakeholders, making tactical use of their specific business interests and influence.
- Conducting advanced, detailed change impact analyses to predict the organizational effects of the transformation, deriving a tailored change strategy, and developing a change roadmap and a change story as the core narrative of the campaign.
- Designing and implementing an integrated communication and action plan to ensure maximum transparency, effectively manage unspoken expectations, and actively guide a change process that is clear and understandable for all stakeholders.
- Active management of all transformation phases, including the setup of robust monitoring mechanisms for continuous progress analysis and forecasting based on recommended and jointly defined KPIs.
- Establishing an agile analysis and adjustment cycle to continuously assess the effectiveness of implemented measures, identify challenges early, and fine-tune the change strategy in time.
- Conducting precise gap analyses to identify skill gaps in the sales team in the context of the new strategic direction, and deriving and developing targeted qualification measures (e.g. coaching, training).
- Comprehensive reduction of resistance to change by turning opposing stakeholder mindsets into proactive change-driving change ambassadors.
- Deep and sustainable realignment of sales structures and processes in full alignment with the company’s overall goals.
- Qualitative and quantitative improvement of sales efficiency and performance as a direct result of the implemented transformation initiatives and capability-building programs.
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.
Gerhard Z.
Last position:
Embedded Software Engineer at Magna Kreisel Electric
- Development of a charging station for electric vehicles
- Tools: C/C++/Matlab/Simulink
- Development and testing of functional software with various communication buses
Michael G.
Last position:
Scrummaster at Xenovo
Planning and monitoring sprints and holding the scheduled meetings
Analyzing and resolving issues in the development process
Error analysis, bug management and correction in individual process steps
Stakeholder management
Documentation and improvement of the development process
Tools: JIRA, Confluence
Mubin I.
Last position:
Software Engineer, Freelancer at Siemens-Linz
- Designed and implemented simulation software for electrical power systems, focusing on dynamic element interaction and user interface optimization using C++, wxWidgets, Windows, and Visual Studio.
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
Üsame T.
Last position:
Java Backend Developer at Porsche Informatik
- Java EE 8 development
- Java 21 and Spring Boot 3 microservices development
- Release management
- Onboarding of new team members
- Owner of an team-internal "Best Code Engineering Award"
Discover over 15,000 top freelancers
Statistics of experts using JSON
Aggregated from the professional profiles of matched freelancers.
Experience
20 years
Position duration
2.1 years
Positions per freelancer
12
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Banking and Finance, Transportation
Certification focus areas
Information Technology, Logistics, Project Management
Bachelor's degree or higher
100%
Master's degree or higher
25%
Certifications per freelancer
2
Most common languages
German, English, Croatian
Speak two or more languages
100%
Based on our profile pool as of 16 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Vienna are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows the share of experts charging within that range.
Average rates of experts in Vienna using JSON
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 16 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
JSON 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 (88%)
- Banking and Finance (50%)
- Transportation (50%)
- Manufacturing (50%)
- Professional Services (50%)
- Automotive (38%)
- Energy (38%)
- Media and Entertainment (38%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What JSON is
JSON, short for JavaScript Object Notation, is a lightweight text format for representing structured data. Its objects, arrays, strings, numbers, booleans and null values are easy for people to read and simple for software to parse. JSON is widely used to move information between web clients, services and databases.
Where it is used
JSON sits at the centre of many digital products and integration projects:
- REST and HTTP API requests and responses
- Configuration for applications, tools and cloud services
- Events exchanged through queues and streaming systems
- Data imports, exports and transformations
- State passed between browser and server applications
Ecosystem and tooling
Strong JSON specialists work across the systems that produce, consume and validate the format. Their toolkit may include JSON Schema, OpenAPI, REST, GraphQL, JavaScript, TypeScript, Python, Java, .NET and command-line utilities such as jq. They also understand serialization libraries, API gateways, message brokers and observability tools.
When companies need expertise
Companies often bring in freelance expertise when an API contract is unclear, integrations fail at system boundaries or a growing payload format needs stronger governance. Vienna teams may work with local specialists on site or collaborate remotely across distributed product and delivery groups. Clear English communication, and German where needed, can support workshops with business and technical stakeholders.
Typical project deliverables
A JSON professional can turn vague integration requirements into consistent, testable outputs:
- JSON Schema definitions and validation rules
- OpenAPI documentation and API contract reviews
- Reliable parsers, serializers and transformation pipelines
- Migration plans for inconsistent or legacy payloads
- Contract tests, fixtures and representative sample data
What quality looks like
Quality work goes beyond producing valid syntax. Experienced professionals define predictable naming, typing, null handling, nesting and error behaviour, while keeping payloads compatible with existing consumers. They consider security, privacy, performance and versioning, then test edge cases and document decisions so future teams can safely extend the format.
Frequently asked questions
Not sure where to start with JSON? These answers cover the essentials.
JSON is used to exchange structured data between web applications, APIs, services and automation tools. Companies also use it for configuration files, event messages, data exports and integrations between systems.
JSON is usually more compact and maps naturally to objects and arrays used in modern application code. XML offers mature document features, namespaces and schema options, so the right choice depends on the integration contract, tooling and data structure.
A strong JSON specialist should understand HTTP, REST, OpenAPI and JSON Schema. Experience with JavaScript or TypeScript, a server-side language, databases, authentication and automated testing is also valuable.
The need depends on the scope. A simple payload change may require focused API knowledge, while a cross-system migration calls for someone who can model contracts, trace dependencies, manage compatibility and test many data conditions.
JSON projects are often well suited to remote collaboration because schemas, API specifications and test cases can be reviewed online. On-site sessions in Vienna can still help when teams need joint workshops about domain models, legacy integrations or release planning.
Ask the JSON specialist to explain naming conventions, validation, error handling, backwards compatibility and test coverage. Review a sample schema or API contract and look for clear assumptions, useful documentation and attention to edge cases.
JSON is a strong choice for many web and service integrations, but it is not universal. Binary formats may suit high-throughput or compact workloads better, while CSV can be simpler for flat tabular data and XML may fit document-heavy integrations.
An effective JSON expert connects data design with the wider system instead of treating payloads as isolated text. They communicate trade-offs clearly, collaborate with product and technical stakeholders, document contracts and leave behind maintainable tests and tooling.
The average hourly rate of freelancers in Vienna, Austria who have used JSON in their recent projects is 88 €, which corresponds to a daily rate of about 704 € based on an 8-hour working day.
Of the freelancers in Vienna, Austria who have used JSON in their recent projects, 100% hold at least a Bachelor's degree and 25% hold at least a Master's degree.
On average, freelancers in Vienna, Austria who have used JSON in their recent projects have 20 years of professional experience, with a single engagement typically lasting around 2.1 years.
The most common languages among freelancers in Vienna, Austria who have used JSON in their recent projects are German (100%), English (100%), and Croatian (25%).
The most common industries among freelancers in Vienna, Austria who have used JSON in their recent projects are Information Technology (88%), Banking and Finance (50%), and Transportation (50%).
The most common business areas among freelancers in Vienna, Austria who have used JSON in their recent projects are Information Technology (100%), Product Development (100%), and Quality Assurance (75%).
Main locations of FRATCH Experts, who have recently used JSON
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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