JSON Expert in Düsseldorf
for reliable data exchange, matched in minutes with vetted freelancersHire experts who design clear JSON schemas, connect REST APIs and transform data between systems. Work with vetted, available freelancers in Düsseldorf who match your technical needs quickly and precisely.
Meet FRATCH Experts in Düsseldorf, who have recently used JSON
Emre S.
Last position:
IT Project Manager | SAP E-Invoicing Outbound at Rohde & Schwarz
Project: Introduction of statutory-compliant electronic invoicing (outbound, Germany) in SAP for an international technology group.
- Project management: Planning, steering and reporting of the E-Invoicing outbound rollout across all affected business areas, including budget and resource coordination.
- UAT: Structured user acceptance test with key users per business area, test cases per invoice scenario, and consolidated test results for decision making.
- Defect management: Handover and tracking of defects in Jira, including validation of the generated invoices against the statutory schemas.
- Cutover, go-live and hypercare: Readiness checks and cutover planning aligned with the statutory deadlines, coordination of go-live and stabilization during hypercare.
- Stakeholder management and reporting: Alignment with Finance, Tax, business departments and IT, preparation of status reports and decision papers, and consistent follow-up of open items.
- Change management and documentation: Communicated process changes to the business departments, enabled key users, and created process and compliance documentation to ensure traceability and audit readiness.
Saruna M.
Last position:
Master's Thesis at Heinrich Heine Universität
- Title: Enhancing Syntactic Awareness in Transformer Language Models for Hindi Dependency Parsing
- Investigated syntactic knowledge captured by transformer language models (RoBERTa, XLM-RoBERTa) for Hindi dependency parsing, a morphologically rich and low-resource language.
- Developed structure-aware model variants (Struct_Roberta_hi, Struct_XLMR) by integrating a CNN-based parser network between transformer layers, inspired by the StructFormer architecture.
- Conducted extensive error analysis including label-wise, distance-based, direction-based, sentence length-based, and LVC/Non-LVC evaluations.
- Evaluated models on downstream NLP tasks (NER, POS tagging) using the IndicXTREME benchmark.
Nils S.
Last position:
Backend System and Web Client for Replacing Electricity Meters for Energy Suppliers at Freelance
Design and implementation of a system for controlling the complete process of installing, removing, and replacing electricity meters by external service providers for an energy supplier
Automated retrieval of orders and available devices through defined interfaces (e.g. from SAP)
Orchestration of the process steps (assignment of meters, processing of meter data, transfer of updated information back to the source system) through a Spring-Boot backend
Provision of a React-based web client for operational tracking and control of orders, e.g. to continue failed process steps or resend notifications
Lutz E.
Last position:
Freelance Software Developer – GoPro MultiCam Control via COHN at Plutos Company UG
- Development of a pilot system to control and monitor multiple GoPro cameras
- Implementation of start, stop, status, media, download, and diagnostic functions via COHN endpoints
- Realization of camera detection, single and group control, as well as stable session/keep-alive logic
- Setup of a download pipeline with queue, retry handling, and temporary files
- Consistent session, folder, and file naming for multi-camera recordings
- Integration of provisioning, certificates, and network operations
Stanislaus S.
Last position:
Security Consultant at Rohde & Schwarz AG at Star Labs GmbH
- Worked on FPGA enhanced network encryption device with secure boot, TPM2.0 and smart card integration for BSI approved usage with Post Quantum Cryptography
- Developed and audited Linux drivers
- Collaborated using GitLab, Gerrit, Confluence and Jira
- Technologies: C, C++, Secure Boot
Alexander R.
Last position:
Business Analyst at Financial Services Provider Landesbank
The Helaba ATLAS project aims to modernize core systems and make them future-proof. As part of the subproject, the existing legacy system for international payments is being replaced by a modern web-based application.
- Analysis of functional and technical requirements
- Analysis and optimization of business processes
- Process modeling
- Preparation and facilitation of workshops
- Defining project scope and prioritizing requirements
- Business process management (analysis, modeling, and optimization)
- Specification of user stories
- Designing business and authorization concepts
- Testing and acceptance
- Designing mockups in Figma
- Creating the UI/UX style guide for web applications Approach: Scrum (agile) Technologies: Jira, Confluence, MS Teams, Conceptboard, Java, Vaadin, Figma
Peter H.
Last position:
Product Owner / Senior Business Analyst
- Analysis of the possibility of transferring market location data to a separate microservice in an overarching web portal
- Development of a more user-friendly target process based on the current process in coordination with users
- Coordination of the related architecture concept with architects/developers
- Coordination of the related epics and user stories with the relevant business departments
- Backlog prioritization and project planning (including effort estimation)
- Testing and acceptance of implemented user stories
- Technologies/tools used: MS Office, Jira, Mural, Kotlin, React, GitHub, MS Azure, SQL, Postman, XML, JSON, Kafka, Balsamiq, BPMN
Sebastian C.
Last position:
Public institution responsible for educational institutions in NRW
- Consulting on processes and execution of load tests, performance tests and technical tests of various applications: web portal, file cloud, email, video conferencing, learning/course platform
- Creating the load test framework
- Programming test scripts (JMeter, Selenium)
- Developing batches to support the evaluation
- Executing load tests and evaluating results, including clear reporting, recommendations for action, and bottleneck analysis
- Managing tasks and collaboration to achieve meaningful load test results
Anouar T.
Last position:
Fullstack Developer Java/Spring Boot at Snipes SE (Deichmann Group)
- Migration of a .NET Core loyalty program for Snipes, used by mobile cash registers in Snipes stores
- Part of the customer’s digitalization strategy in an agile, cross-functional team with a high level of ownership
- Connecting interfaces to third-party systems (e.g. Brandung, CDS)
- Quality assurance through automated tests
- Carrying out developer, unit, and integration tests
- Patterns & methods used: Clean Code, microservice architecture, agile development with SCRUM
- Technologies & tools used: Spring Boot, Java 23, Java Persistence API (JPA), Azure DevOps, Azure Key Vault, Azure PostgreSQL, Docker & Kubernetes, Git, Graylog, Grafana, JUnit, SonarQube, Jira, Confluence, Prometheus, GitLab, GitLab CI/CD, Visual Studio Code
Jürgen V.
Last position:
Instructor / Trainer at SAP Training Company
- Instructor / Trainer
- SAP applications in SAP S/4 HANA - Sales, Sourcing Procurement, Logistic Execution, SAP Foundation
- SAP S/4 HANA - Fiori UX and Fiori Launchpad
- Cross-module MM application - Sourcing & Procurement
- Business processes SAP S/4 HANA Procurement
- Purchasing processes SAP S/4 HANA MM
- Incoming processes SAP S/4 HANA MM
- Supplier invoicing SAP S/4 HANA MM
- Pricing & plant determination SAP S/4 HANA MM
- Automation in SAP S/4 HANA MM
- Business processes SAP S/4 HANA Pre & After Sales
- Sales processes SAP S/4 HANA Sales
- Delivery processes SAP S/4 HANA Sales
- Billing SAP S/4 HANA Sales
- Pricing SAP S/4 HANA Sales and Storage Rooms and Lean-EWM
- Automation in SAP S/4 HANA Sales
- SAP S/4 HANA – SAP Private Cloud – Release 2023
Çağrı S.
Last position:
Freelance Art Director / Motion Designer at 12yapım
- Direct and produce a monthly AI-generated Reels series for a retail client — 7 episodes completed, now running at 2/month.
- Own the full pipeline: direct visual prep, write JSON prompts for AI video generation, finalize cut, color, and sound.
- Deliver each video in 2-3 days from brief to final.
Jacqueline H.
Last position:
Kitchen Appliance Manufacturer
Setting up and enhancing an international subscription management system
Migrating and decommissioning a Hybris-SAP system and integrating Zuora
Implementing numerous interfaces to various systems (external and internal)
Setting up and improving monitoring with Grafana, Prometheus, and Databricks
Introducing logging with Loki
Implementing business requirements using jQuery, Thymeleaf, Spring Boot, Java, Go, and Python
Adjusting and extending the GitLab CI pipelines
Setting up and extending infrastructure as code with Terraform and ArgoCD on AWS
Setting up and running E2E and performance tests
Expanding the Databricks business intelligence solution to provide various KPIs
Responsibilities: Architecture, DevOps, development, unit tests, coaching employees and apprentices, E2E, smoke, and integration tests, agile methods consulting (Kanban, Scrum)
Technologies and methods: Java, Go, Kotlin, Node.js, Spring Boot, SOAP/REST, Quarkus, Thymeleaf, Vaadin, Slack, Jira, Confluence, IntelliJ, GitLab, SQS, Kafka, AWS, Kubernetes, Terraform, Maven, Gradle, GitLab CI, Databricks
Daniel M.
- SaaS including subscription management and mobile app
Discover over 15,000 top freelancers
Statistics of experts using JSON
Aggregated from the professional profiles of matched freelancers.
Experience
16 years (Germany: 19 years)
Position duration
1.3 years (Germany: 5.2 years)
Positions per freelancer
14
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
100% (Germany: 89%)
Master's degree or higher
78% (Germany: 56%)
Doctorate
11% (Germany: 10%)
Certifications per freelancer
3 (Germany: 2)
Most common languages
German, English, French
Speak two or more languages
100% (Germany: 98%)
Based on our profile pool as of 29 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Düsseldorf 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 Düsseldorf 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 29 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 (92%)
- Retail (69%)
- Banking and Finance (62%)
- Manufacturing (54%)
- Professional Services (38%)
- Automotive (31%)
- Education (31%)
- Media and Entertainment (31%)
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. It uses objects, arrays, strings, numbers, booleans and null values, making information easy for applications and people to read. JSON is language-independent and is widely used for data exchange across web, mobile and cloud systems.
Where it is used
JSON sits between many parts of modern software and business infrastructure. Common deliverables include:
- REST API request and response payloads
- Configuration files for applications and cloud services
- Event messages and document data in distributed systems
- Imports, exports and transformations between business platforms
Its predictable structure supports frontend interfaces, backend services, automation workflows and integrations across industries. In Düsseldorf, companies often use it within connected enterprise, retail, logistics and industrial systems.
Ecosystem and tooling
Strong JSON specialists work with REST, GraphQL and webhooks, as well as JSON Schema and OpenAPI for documenting and validating data contracts. They may use JavaScript, TypeScript, Python, Java, PHP or C# to produce and consume JSON. Familiarity with Postman, curl, API gateways, message brokers and tools such as jq helps them inspect and troubleshoot payloads efficiently.
When expertise matters
Freelance expertise becomes valuable when inconsistent payloads, unclear ownership or fragile integrations slow delivery. Typical signs include:
- API contracts change without reliable validation
- Different systems interpret dates, identifiers or missing values differently
- Large payloads create performance or security concerns
- A migration requires dependable data mapping and testing
A specialist can define schemas, document edge cases, introduce contract tests and make transformations traceable. This reduces integration risk without forcing a company to rebuild every connected system.
What strong professionals deliver
The best professionals treat JSON as a data contract, not just a notation. They choose consistent naming, nesting and types; handle optional fields deliberately; and distinguish null, empty and missing values. They also consider encoding, backward compatibility, validation errors, sensitive data and payload size. Clear documentation and representative test fixtures make the result easier for other teams to use.
Collaboration and quality
JSON work can usually be delivered remotely because schemas, payload samples, API specifications and test results are easy to share. On-site collaboration in Düsseldorf can help when specialists must work closely with product, security or integration teams. Assess quality through a practical review of sample payloads, schema decisions, error handling, versioning strategy and the professional’s ability to explain trade-offs in plain language.
Frequently asked questions
Need clarity? These are the questions we hear most often about JSON.
JSON is mainly used to exchange structured data between web applications, mobile apps, APIs, databases and cloud services. Companies also use it for configuration, event messages, data exports and integrations between business systems.
JSON is generally more compact and maps naturally to objects and arrays used in application code. XML offers richer document features, namespaces and attribute support, so the right choice depends on validation needs, existing systems and the type of data being exchanged.
JSON expertise is strongest when combined with REST API design, JSON Schema, OpenAPI, authentication and automated testing. Experience with a programming language, databases, message queues and observability also helps when data crosses several services.
The required level depends on the scope rather than the format alone. A simple payload mapping may need focused integration skills, while a shared API contract requires experience with versioning, validation, security, compatibility and failure handling.
JSON projects are often well suited to remote collaboration because teams can share schemas, API specifications, payload samples and test results online. For Düsseldorf-based companies, on-site sessions can still be useful during workshops involving German-language stakeholders, security reviews or complex integration planning.
JSON is often preferable for machine-to-machine APIs because its syntax is strict, widely supported and straightforward to parse. YAML can be easier for humans to edit, especially in configuration, but its flexibility may create interpretation issues unless teams apply clear rules.
Ask the specialist to review a realistic payload and explain choices around types, optional fields, errors and backward compatibility. A strong JSON professional will also propose validation, documentation and tests rather than focusing only on making one example parse.
JavaScript Object Notation is the full name of JSON, but it is not limited to JavaScript. Libraries for languages such as Python, Java, C#, PHP and Go can parse and generate it, allowing the same data contract to connect different technology stacks.
The average hourly rate of freelancers in Dusseldorf, Germany who have used JSON in their recent projects is 101 €, which corresponds to a daily rate of about 809 € based on an 8-hour working day.
Of the freelancers in Dusseldorf, Germany who have used JSON in their recent projects, 100% hold at least a Bachelor's degree, 78% hold at least a Master's degree, and 11% hold a doctorate.
On average, freelancers in Dusseldorf, Germany who have used JSON in their recent projects have 16 years of professional experience, with a single engagement typically lasting around 1.3 years.
The most common languages among freelancers in Dusseldorf, Germany who have used JSON in their recent projects are German (100%), English (100%), and French (15%).
The most common industries among freelancers in Dusseldorf, Germany who have used JSON in their recent projects are Information Technology (92%), Retail (69%), and Banking and Finance (62%).
The most common business areas among freelancers in Dusseldorf, Germany who have used JSON in their recent projects are Information Technology (100%), Product Development (92%), and Quality Assurance (62%).
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.
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