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JSON Experts in Berlin

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Hire experts who design clean JSON data models, build and validate API payloads, and keep JavaScript Object Notation easy to exchange across services, apps, and integrations. Get fast, precise matching with vetted, available freelancers.

Meet FRATCH Experts in Berlin, who have recently used JSON

Verified expert

Syed Abdul

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Senior Software Engineer

Berlin
Syed Abdul

Last position:

Senior Software Engineer at Giant Eagle

  • Designed and developed AI-powered document processing solutions using Python, OCR, NLP, and Large Language Models (LLMs) to automate extraction, validation, and classification of financial documents, reducing processing time by 75%.
  • Built intelligent multi-stage workflow automation pipelines integrating AI services, machine learning models, and enterprise systems to streamline financial operations and improve data quality.
  • Developed reusable AI-driven transformation frameworks capable of processing structured and unstructured document formats (XML, CSV, JSON, TXT, DAT) and normalizing them into unified business schemas.
  • Designed and developed Python-based REST APIs and backend services supporting enterprise finance applications and high-volume data processing workloads.
  • Built scalable data synchronization pipelines between Oracle CFIN and SQL databases, incorporating machine learning models for cash-flow forecasting and AP/AR anomaly detection.
  • Architected and deployed Apache Airflow workflows to orchestrate AI-powered data pipelines, automating end-to-end processing from document ingestion through financial system integration.
  • Led the migration of critical enterprise integrations from MuleSoft to Python-based services, improving maintainability, performance, and operational flexibility while preserving complete data integrity.
  • Managed the full API lifecycle including solution design, implementation, documentation, deployment, monitoring, and production support for mission-critical financial systems.
  • Collaborated directly with finance stakeholders to identify business challenges, define solution requirements, and deliver measurable operational improvements through automation and AI-driven workflows.
  • Worked closely with cross-functional engineering and business teams to rapidly iterate on features, improve processes, and drive successful adoption of AI-enabled solutions.
  • Provided technical leadership through architecture reviews, technology decisions, code reviews, and engineering best practices across integration and automation initiatives.
  • Mentored developers, established coding standards, and contributed to improving software quality, maintainability, and delivery effectiveness across projects.
  • Provided production support during critical month-end and quarter-close financial processes, performing root-cause analysis and implementing rapid fixes to ensure system reliability and data accuracy.
Verified expert

Benjamin Faas

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Freelance Product Manager, Product Owner, Scrum Master & Agile Coach

Berlin
Benjamin Faas

Last position:

Freelance Product Manager, Product Owner, Scrum Master & Agile Coach at Freelance

  • Freelance product owner, scrum master and agile coach in various projects spanning from local agencies to multinational corporations in diverse industries.

  • Last projects:

  • Adevinta: Technical Project Manager responsible for coordination of several sub-workstreams building the world’s largest classifieds multi-tenant platform.

  • Aroundhome (a ProSiebenSat.1 company): Product Manager implementing and verifying on the business side a concept for digital qualification of user requests for matching service providers.

  • Peek & Cloppenburg Düsseldorf: Product Manager Mobile advising on and guiding the rebuild of Android and iOS apps.

  • Visual Meta GmbH (an Axel Springer company), Berlin: Director Product co-leading the Product & Engineering department together with the Director Engineering.

  • Responsibilities at Visual Meta GmbH:

  • Define and deliver a 3–5 year horizon product strategy including a product vision & mission connecting to existing company strategy and strategies from adjacent departments.

  • Refine an existing OKR process together with OKR master and directors of other departments to increase focus and outcome.

  • Support the Director Engineering in creating a platform transformation strategy to transform a monolithic on-premise tech stack into a service-oriented, cloud-based architecture and establish a domain-based organizational setup.

  • Accountability for a motivated and talented team of 5 head-level colleagues and 17 operational team members from product management, data and UX/UI design.

  • Key achievements at Visual Meta GmbH:

  • Defined and delivered a 3–5 year horizon product strategy including a product vision & mission.

  • Increased focus within OKR process by moving from 10 company-level objectives to 2 and from several hundred team-level key results to a few dozen.

  • Created a career path framework for the product team defining roles and responsibilities from junior to head level positions.

Verified expert

Sunish Bharathan

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Technical Program Manager . Engineering Delivery & AI Systems

Teltow
Sunish Bharathan

Last position:

AtlasMind - Production AI assistant for Jira at Mercedes Benz Innovation Labs Gmbh

  • Converts natural language into JQL using RAG and pgvector. Returns structured JSON with a query, chart spec, and plain-text answer. A two-stage router answers general questions without touching the JQL pipeline at all.
  • Interchangeable LLM backends: Ollama, vLLM, Groq, Anthropic Claude, AWS Bedrock - switchable at runtime, no code changes. Self-healing JQL: on Jira validation failure, feeds error back to LLM, retries up to 4 times. OCI Vault for secrets. Deployed on Oracle Cloud A1 with GPU inference over Tailscale private network. Open source.
Verified expert

Santhosh Kannan

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Freelance Software Engineer

Berlin
Santhosh Kannan

Last position:

Freelance Software Engineer at Zalando SE

  • Support Authorization as a Service initiative for enterprise-scale authorization platform
  • Incorporate comprehensive observability solutions into authorization infrastructure
  • Provision and manage AWS infrastructure for authorization services
  • Mentor development team on AWS and Kubernetes best practices
  • Tech Stack: Java/Kotlin, Golang, Python, OPA, Spring Boot, AWS, Kubernetes, Terraform, ELK Stack, Prometheus, Grafana
Verified expert

Imran Ali

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Software Engineer II

Berlin
Imran Ali

Last position:

Software Engineer II at LivePerson Germany GmbH

  • Led development of 15+ microservices (Java 17, Spring Boot) driving customer interactions; migrated from on-prem to GCP Kubernetes, improving scalability and reducing infra cost by 20%.
  • Optimized user services with CouchDB caching and API refactoring, cutting response times by 35% and enhancing customer experience.
  • Implemented canary deployments, FluxCD GitOps, and CI/CD optimizations in GitLab, reducing release lead time by 25% and enabling zero-downtime rollouts.
  • Set up Grafana health checks and Anodot alerts for latency, error, and throughput monitoring, reducing MTTR by 40%.
  • Built secure APIs using OAuth2, DPoP, and Gatekeeper, integrated REST and GraphQL, and achieved 90%+ test coverage with unit and E2E tests.
  • Mentored junior developers, promoted Agile best practices, and collaborated cross-functionally to deliver high-impact, reliable customer-facing features.
Verified expert

Hamza Khan

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Academic Research Contributor in Health Sector (Volunteer)

Berlin
Hamza Khan

Last position:

Academic Research Contributor in Health Sector (Volunteer)

  • Acted as technical consultant to optimize multi-layer ensemble models combining ResNet, CNN-BiGRU-Attention, and XGBoost.
  • Guided implementation of a Logistic Regression meta-learner to solve class imbalance problems, achieving 92.86% accuracy and 0.9644 AUC on PTB-XL and Chapman-Shaoxing datasets.
Verified expert

Can Savastürk

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Software Development for People

Berlin
Can Savastürk

Last position:

Platform Engineer at ClimateChoice

In a lean, execution-focused environment, I took ownership beyond a narrow engineering lane, shaping and implementing systems across backend, data, and infrastructure. Partnered directly with the three founders in a fast-moving, high-stakes environment, turning strategic priorities into concrete technical decisions and production outcomes.

  • Owned core platform development across backend (Django/Rest Framework/Postgres), ETL (Python/Dagster), infrastructure (Terraform/Kubernetes/AWS), and frontend (typescript/react) for a climate-tech SaaS product, driving continuous cross-stack development across five repositories from October 2021 to this day.
  • Architected and owned a standalone internal Python scoring framework for CRC assessments, using YAML-driven rules and metaprogramming to enable non-technical users to define complex evaluation logic without hardcoded implementations.
  • Built and stabilized ETL and scraping pipelines using Dagster and Scrapfly, improving document ingestion, tagging, retry behavior, deployment flow, and operational resilience.
  • Contributed to platform modernization and reliability through Django/Python upgrades, Postgres/RDS and EKS changes, CDN/TLS updates, test and performance improvements, and observability hardening.
  • Drove backend engineering for product features, translating requirements into technical specifications, API contracts, data structures, and scalable implementation plans.
Verified expert

Mathias Wilhelm

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Development of an AI-driven social media automation for identifying topics, generating text, and publishing content

Berlin
Mathias Wilhelm

Last position:

Implementation of an on-premise OCR solution with information extraction at Mindhopper GmbH

  • Insurance service provider*

Challenge: Business-critical documents were processed through external OCR providers, with ongoing costs, dependency, and data privacy risks for sensitive insurance data.

Implementation:

  • Architecture and production implementation of an on-premise OCR solution with full data ownership
  • Methods for recognizing document structures as the basis for automated further processing
  • ML-, NLP-, and LLM/VLM-based information extraction, especially from invoices and quotations

Success: Replaced external providers: full data ownership, GDPR-compliant processing, and 75% lower recurring OCR costs per year

Used technologies: Python, Docker, Microservices, FastAPI, PyTorch, Torchvision, MongoDB, MySQL

Verified expert

Mario Jelinski

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Architect / Developer

Berlin
Mario Jelinski

Last position:

Architect / Developer at handyhase

  • Overhaul of the entire design and implementation of new UI/UX aspects using React
  • Planning of the software architecture and structuring of the project for long-term scalability using Git for version control
Verified expert

Vili Dhamo

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Senior Data Engineer, Data Architect, Software Engineer

Neuenhagen
Vili Dhamo

Last position:

Technical Lead, Data Engineer at Mercedes-Benz Consulting

  • Optimized the data architecture (medallion) to better decouple processing stages and improve transparency and reproducibility
  • Ensured technical quality of data processing in Databricks by introducing schema enforcement, data quality checks and a structured data architecture
  • Orchestrated pipelines with Azure Data Factory
  • Professionalized and automated the development and deployment process by integrating Git and GitHub Actions
  • Led the Data Engineering team (3 members) in a functional role
  • Conducted workshops to optimize and stabilize the data platform and the development process
  • Collected and prioritized new requests, maintained the product backlog
  • Technologies: Microsoft Azure (Data Lake, Data Factory), Databricks, Apache Spark (PySpark), Python, SQL, Git, Confluence, Power BI, Power Apps, Dataverse, MS SharePoint, Mural
Verified expert

Christian Golecki

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Enterprise Program Stabilization | IT Program Delivery | System Integration | Turnaround

Zeuthen
Christian Golecki

Last position:

Product Owner – Redesign of an iOS and Android SaaS application platform at iApps Technologies GmbH

  • Led the redesign of an iOS and Android B2B SaaS solution.
  • Developed the product vision and strategy and designed the platform architecture.
  • Worked closely with cross-functional teams to create a user-centered, forward-looking product.
  • Identified market trends and analyzed feedback from stakeholders and customers.
  • Developed a well-thought-out feature set.
  • Led the product design and development process.
  • Created Balsamiq wireframes.
  • Conducted comprehensive market and competitor analysis.
  • Defined the product roadmap and feature scope, managed and prioritized the backlog.
  • Crafted and wrote epics and user stories.
  • Briefed UI designers and reviewed and approved Figma layouts.
Verified expert

Ottavio Braun

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AI Systems Architect

Berlin
Ottavio Braun

Last position:

Semantic Test Framework for LLMs

Verified expert

Daniel Stopp

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Frontend and Web Developer

Berlin
Daniel Stopp

Last position:

Frontend and Web Developer at Datalyze Solutions

  • Frontend development and implementation of various designs (landing pages, overview pages)
  • Responsible for the content and updates of the Datalyze Solutions company website
  • Joint planning and development of an admin application for listing and locating real estate projects (CBRE)
  • Joint planning and development of extensive solutions for automatic staff allocation in plants (Bosch)
  • Backend development of various small projects with different stacks
  • Tech stack: GitLab CI/CD, Elixir, Phoenix Framework, Ecto, PostgreSQL, Docker, Hetzner, Traefik, NGINX, Python, Flask, Next.js/React, Leaflet, GeoServer, TypeScript, MongoDB
Verified expert

René Pfisterer

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Founder and CEO

Berlin
René Pfisterer

Last position:

Full Stack Developer at XPS Software

  • Industry: B2B
  • Headless frontend with AEM integration
  • Key challenge: Migrating a PWA application in live operation based on .NET and legacy code; the entire application must be converted to React and Express.js/TypeScript
  • Technical frameworks: Tailwind, XML, JavaScript, Caddy, ReactJS, Express.js, REST API, JSON
  • Cloudflare CDN
  • Caddy server with GitHub CI/CD pipeline

Discover over 15,000 top freelancers

Statistics of experts using JSON

Aggregated from the professional profiles of matched freelancers.

Experience

18 years (Germany: 19 years)

Position duration

2.4 years (Germany: 1.9 years)

Positions per freelancer

12 (Germany: 14)

Top business areas

Information Technology, Product Development, Project Management

Top industries

Information Technology, Professional Services, Media and Entertainment

Certification focus areas

Information Technology, Product Development, Project Management

Bachelor's degree or higher

96% (Germany: 88%)

Master's degree or higher

64% (Germany: 56%)

Doctorate

18% (Germany: 11%)

Certifications per freelancer

1 (Germany: 2)

Most common languages

German, English, Spanish

Speak two or more languages

94% (Germany: 98%)

Based on our profile pool as of 30 Aug 2026.

Daily rate distribution

0 3 6 9 12
<€320 €320-​480 €480-​640 €640-​800 €800-​960 €960-​1120 €1120+

The chart shows how the daily rates of freelancers in this technology in Berlin 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 Berlin using JSON

Rates are based on recent contracts and do not include FRATCH margin.

800
600
400
200
Rate comparison chart
Daily rate avg. 727 €
Germany avg. 761 €

The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.

800
600
400
200
Rate comparison chart
Median rate 736 €
Germany median 760 €

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

What JSON is

JSON, short for JavaScript Object Notation, is a simple text format for structured data. Teams use it to move information between APIs, web apps, services, and data pipelines because it is compact, readable, and easy to parse in many systems.

Where it fits

  • API requests and responses
  • Configuration files and feature flags
  • Event payloads and webhook bodies
  • Data export and import feeds
  • Logs, fixtures, and test data

JSON is rarely the final product on its own. It is the exchange layer that keeps systems aligned, especially when different tools, languages, or teams need the same structure.

Skills that matter

Strong JSON specialists know how to design stable object structures, choose clear field names, and avoid brittle nesting. They also understand encoding, escaping, null handling, arrays, and the difference between strict parsing and tolerant ingestion.

Tooling around it

Working well with JSON often means using validators, schema tools, and API clients. In practice, teams pair JSON with OpenAPI, JSON Schema, GraphQL responses, message brokers, and backend frameworks that emit or consume structured payloads.

When companies bring in help

Companies usually look for freelance JSON expertise when an API contract keeps breaking, data between services no longer matches, or configuration has become hard to maintain. In Berlin, this often comes up in product teams, SaaS companies, and data-heavy platforms that need remote specialists who can work cleanly with existing code and documentation.

What strong professionals deliver

  • Stable payload and schema design
  • Validation rules and error handling
  • Cleanup of inconsistent data structures
  • Integration support across services and tools
  • Documentation that other specialists can follow

Good JSON professionals make structures predictable. They reduce parsing errors, keep contracts readable, and leave teams with data that is easier to extend without breaking downstream systems.

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Frequently asked questions

Not sure where to start with JSON? These answers cover the essentials.

JSON is used to store and exchange structured data between systems. Companies rely on it for API payloads, configuration, event messages, and imports or exports that need to stay readable and easy to process. It is one of the most common ways to move data across web apps and services.

Yes. JSON is the short name, and JavaScript Object Notation is the full name. In practice, both refer to the same text-based format for structured data.

A strong JSON specialist helps when payloads become inconsistent, APIs fail validation, or nested data is hard to maintain. Teams also bring in help when they need cleaner schema design, safer transformations, or better documentation for other specialists.

JSON is usually lighter and easier to read than XML, which makes it a common choice for APIs and modern application data. XML still appears in older systems and document-heavy integrations, but JSON is often preferred when teams want simpler structures and less parsing overhead.

A good JSON freelancer usually also knows API design, JSON Schema, data validation, and one or more backend or frontend stacks that consume structured data. Experience with OpenAPI, webhooks, and message-based integrations is often useful too.

JSON itself is simple, but production work is not. Simple formatting help may need only basic familiarity, while API contracts, schema governance, and data migrations need someone who has handled real integration problems before.

Yes, JSON work is usually well suited to remote collaboration because it centers on files, payloads, and interface contracts. For teams in Berlin, that often means a specialist can join remotely and still work closely with product, backend, and QA specialists. On-site time is only needed when the team wants tight workshops or rapid cross-functional review.

Look for clean structures, consistent naming, and careful handling of edge cases such as null values, arrays, and escaping. A strong JSON professional also explains trade-offs clearly, writes useful validation rules, and leaves data that other specialists can trust without extra cleanup.

The average hourly rate of freelancers in Berlin, Germany who have used JSON in their recent projects is 91 €, which corresponds to a daily rate of about 727 € based on an 8-hour working day.

Of the freelancers in Berlin, Germany who have used JSON in their recent projects, 96% hold at least a Bachelor's degree, 64% hold at least a Master's degree, and 18% hold a doctorate.

On average, freelancers in Berlin, Germany who have used JSON in their recent projects have 18 years of professional experience, with a single engagement typically lasting around 2.4 years.

The most common languages among freelancers in Berlin, Germany who have used JSON in their recent projects are German (97%), English (94%), and Spanish (9%).

The most common industries among freelancers in Berlin, Germany who have used JSON in their recent projects are Information Technology (94%), Professional Services (44%), and Media and Entertainment (41%).

The most common business areas among freelancers in Berlin, Germany who have used JSON in their recent projects are Information Technology (97%), Product Development (94%), and Project Management (56%).

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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