JSON Schema Experts in Germany
in minutes from over 15,000 CVs with the power of AI.Hire experts who define data contracts, build validation rules, and align API payloads across services and teams. They work with schema drafts, OpenAPI-linked request bodies, and tooling for safe change control, with fast, precise matching to vetted, available freelancers.
Meet FRATCH Experts in Germany, who have recently used JSON Schema
Collin Kempkes
Last position:
Lead Fullstack Developer at Freelance
- Development of cloud native applications to provide a multi-vendor marketplace for different digital assets (e.g. NFTs)
- Design and operation of a microservice architecture using Nest.js, MySQL, Redis, Hasura, Algolia, Docker and Serverless
- Design and operation of a streaming data architecture using Kafka (with JSON Schemas)
- Creation of CI/CD pipelines with GitHub Actions for automated deployment of applications
- Testing and evaluating new technologies for more stable, faster, safer and more sustainable application development
- Building the full infrastructure with Terraform in AWS
- Integration of Stripe to handle international payments
- Use of Algolia for real-time search of digital assets on the platform
- Presenting results to stakeholders and running internal meetups
- Federation of services with GraphQL and Hasura
- Discussions about architecture decisions in the IT landscape and their impact
- Use of message queues for app-internal communication and component encapsulation
- Advising internal staff on the implementation of business and technical requirements
- Test Driven Development: unit, integration and E2E testing using JUnit
- Use of Next.js/React with SASS/SCSS for frontend applications
- Use of Vue.js with SASS/SCSS for frontend applications
- Integration of security-related mechanisms (JWT tokens with Auth0, OAuth, OIDC, IP guards, BOLA, secret vaults)
- Creation of microfrontends using Retool for fast prototyping and testing of functionality
- Use of nx monorepo with nrwl
Markus Oberhammer
Last position:
Lead E-Solution Architect & Senior Requirements Engineer at Zasterbot-Oracle
- Clarification of project goals, scope, and functional target vision for building the AI-based knowledge base.
- Deriving the initial architecture and implementation strategy for the Zasterbot chatbot, including defining the MVP and expansion phases.
- Developing a functional target vision for building a structured knowledge base and integrating a future chatbot.
- Deriving and prioritizing use cases for information retrieval and provision by the chatbot.
- Modeling data structures and flows for effectively organizing the knowledge base on the Base44 platform.
- Designing and implementing data models for storing and linking relevant information.
- Developing processes for extracting, analyzing, and preparing raw data for the knowledge base.
- Ensuring data consistency and quality as the foundation for the future chatbot.
- Planning the integration of large language models (LLMs) and retrieval-augmented generation (RAG) for precise and context-aware responses.
- Implementing features for analyzing and visualizing data from the knowledge base.
- Using the Base44 platform with JSON-schema-based entities and a flexible permission model.
- Implementing Deno functions for backend logic, event processing, and external API integration.
- Integrating OpenAI services for initial data analysis.
Franck Fondjo Ndetta
Last position:
Multiproject Manager / Senior Business Analyst at MANN&HUMMEL
- Overall management of several project streams: mechanical development, IoT integration, software development, plant design, validation
- Management of an international project team made up of mechanical engineers, electronics engineers, software developers, designers, and external suppliers
- Coordination of global stakeholders from Germany, France, India, China, and the USA
- Planning, controlling, and reporting across all project levels: schedule, budget, resources, and deliverables (PMI-oriented)
- Moderation of steering committees, technical workshops, and milestone decisions
- Responsibility for requirements management and prioritization in the overall context (IoT, cloud, mechanical integration, safety standards)
- Quality assurance and test strategy: validation of filtration results, system behavior, plant integration
- Supplier management and procurement involvement for components, logistics, and assembly
- Risk management and escalation handling for technical, regulatory, or cross-country deviations
- Go-to-market preparation: coordination of product documentation, CE certification, training, and handover to service & sales
- Methods: multiproject management according to PMBOK, hybrid model SCRUM + classic milestone planning, stage-gate model
- Tools: MS Project, Excel, Jira, Confluence, Miro, MS Teams, SharePoint, CAD/CAE systems, test and validation software
- Technologies: OPC UA, MQTT, Siemens S7, IO-Link, Modbus, REST APIs, SCADA, monitoring dashboards, sensors & control technology, CE-compliant housing design, ISO standards
Katharina Schachmatov
Last position:
AI Engineer
- Designed and implemented end-to-end automated workflows for extracting structured data from semi-structured PDF documents including invoices and medical reports
- Leveraged Optical Character Recognition (OCR) technology and large language models to parse documents and generate validated JSON schemas
- Engineered prompt optimization strategies and rule-based classification hierarchies to enhance parsing accuracy across diverse document layouts
- Established quality assurance framework using evaluation metrics to validate output against ground truth datasets with 96% accuracy
Jan Beckert
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
Adithya Naik
Last position:
Vehicle Classification and Detection using Neural Networks
Detecting and classifying vehicles in images and video for traffic monitoring
- A YOLO + Faster R-CNN model built for real-world traffic and autonomous-vehicle scenarios. Awarded Best Paper Award at St Joseph Engineering College, March 2025.
What it does
- The model takes images or video frames and both localizes and classifies vehicles by type, making it usable for downstream applications such as traffic-flow monitoring or perception in autonomous-vehicle systems.
What I did
- Combined YOLO (for fast detection) with Faster R-CNN (for higher-precision classification), rather than relying on a single architecture, trading off speed and accuracy where each mattered most.
- Achieved 90% mean Average Precision (mAP), evaluated using IoU-based metrics rather than just raw accuracy, to properly reflect localization quality.
- Handled the full data processing and evaluation pipeline in Python using TensorFlow and OpenCV.
- The accompanying paper was awarded the Best Paper Award by the Department of CSE at St Joseph Engineering College.
Tech stack: Python, TensorFlow, OpenCV, YOLO, Faster R-CNN
Michael Menzel
Last position:
Deutsche Bahn
- Implemented accessibility audit recommendations for the ICE onboard portal to improve usability for screen reader and keyboard users
- Migrated end-to-end tests from Cypress to Playwright
- Refactored components to meet accessibility standards
- Introduced Prettier for consistent code formatting
Markus Troschinski
Last position:
Senior Software Engineer at Krauss Maffei Technologies GmbH
- Architecture and design of the application
- Development of new features
- Integration with AWS backend (GraphQL, REST)
- Deployment on AWS
- Gatsby, React, Redux, Material UI, TailwindCSS, ChartJS, Plotly, GraphQL, GitLab
Matthias Max
Last position:
Founder at CaseOS Low-Code Platform
Georg Ledermann
Last position:
Solectrus
- Dashboard application for visualizing power generation and consumption, as well as profitability calculations of a photovoltaic system.
- The software is strictly modular and versatile, also usable on devices like Raspberry Pi or NAS systems, and offers connectivity to a wide range of PV installations.
- A steadily growing community appreciates the intuitive interface and high reliability of the tool.
- The source code is publicly available (open source), and development is funded through a sponsorship model.
- Technologies: Ruby on Rails, InfluxDB, Docker, MQTT
Discover over 15,000 top freelancers
Statistics of experts using JSON Schema
Aggregated from the professional profiles of matched freelancers.
Experience
16 years
Position duration
2.6 years
Positions per freelancer
10
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Automotive, Professional Services
Certification focus areas
Information Technology, Product Development, Project Management
Bachelor's degree or higher
88%
Master's degree or higher
63%
Certifications per freelancer
1
Most common languages
German, English, French
Speak two or more languages
100%
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 JSON Schema
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
Data contracts
JSON Schema defines the shape of JSON data. Teams use it to validate API requests, event payloads, config files, and form submissions before bad data reaches production. Strong specialists turn loose JSON into clear, shared contracts.
Common work
- Describe required and optional fields
- Set types, formats, enums, and nesting rules
- Align schemas with REST and event-driven APIs
- Keep versions compatible across services
Tooling
Good work with JSON Schema often sits next to OpenAPI, Ajv, Spectral, and CI checks. Specialists also know how schemas are stored, reviewed, and reused across repositories so teams can validate consistently.
Why hire help
Companies bring in freelance experts when validation rules have grown messy, API changes break clients, or schema design needs a clean reset. In Germany, this is common in product teams, data-heavy platforms, and system integrations where precise payloads matter.
What strong experts do
They write schemas that are strict where needed and flexible where it helps. They understand draft differences, nested objects, arrays, references, and formats, and they can explain trade-offs to backend, frontend, and integration teams.
Good fit
JSON Schema specialists are a fit when you need safer APIs, better input validation, or clearer data contracts between services. They also help when forms, configuration, and documentation must stay in sync without manual checks.
Frequently asked questions
What clients ask us most about JSON Schema — answered in short.
JSON Schema is used to define and validate the structure of JSON data. Companies use it for API payloads, configuration files, event messages, and form data so systems can reject invalid input early. It is especially useful when many services or teams share the same data shape.
JSON Schema focuses on describing and validating JSON data itself. OpenAPI uses schema definitions inside a broader API specification that also covers paths, methods, and responses. If you need only data validation, JSON Schema is the smaller and cleaner tool; if you need the full API contract, OpenAPI is usually the better fit.
Bring in a JSON Schema specialist when validation rules are hard to maintain, schemas need refactoring, or API contracts keep breaking downstream systems. It also helps when a team is adopting schema-first design or needs support reviewing existing schemas for clarity and compatibility. Freelance help is useful when the work is important but not full-time.
A strong JSON Schema expert usually understands APIs, REST, event payloads, and validation tooling such as Ajv. Knowledge of OpenAPI, YAML, CI pipelines, and test automation is also valuable. For product teams, clear communication matters just as much as syntax.
The right JSON Schema expertise depends on the scope. Simple field validation can be handled quickly, while shared contracts across services, versioning, and backward compatibility need deeper experience. If the schemas affect production APIs, choose someone who has worked with strict validation and change control before.
Yes, JSON Schema work is often well suited to remote collaboration. Most tasks are document-based, so reviews, pairing, and schema changes can happen across locations with little friction. For teams in Germany, remote specialists are practical when English documentation and clear review processes are in place.
Look for clean schema design, correct use of required fields, references, and formats, and a clear explanation of trade-offs. A good JSON Schema professional writes schemas that are easy to maintain and consistent with the rest of the API contract. They should also be able to show how they test validation and handle edge cases.
A JSON Schema freelancer should know which draft version the project uses and how the schemas will be consumed. It helps to understand whether the work supports APIs, configuration, forms, or events, because each one has different validation needs. Good upfront context reduces rework and keeps the contract precise.
The average hourly rate of freelancers in Germany who have used JSON Schema in their recent projects is 102 €, which corresponds to a daily rate of about 813 € based on an 8-hour working day.
Of the freelancers in Germany who have used JSON Schema in their recent projects, 88% hold at least a Bachelor's degree and 63% hold at least a Master's degree.
On average, freelancers in Germany who have used JSON Schema in their recent projects have 16 years of professional experience, with a single engagement typically lasting around 2.6 years.
The most common languages among freelancers in Germany who have used JSON Schema in their recent projects are German (100%), English (100%), and French (40%).
The most common industries among freelancers in Germany who have used JSON Schema in their recent projects are Information Technology (100%), Automotive (60%), and Professional Services (60%).
The most common business areas among freelancers in Germany who have used JSON Schema in their recent projects are Information Technology (100%), Product Development (100%), and Quality Assurance (60%).
Main locations of FRATCH Experts, who have recently used JSON Schema
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
