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JSON Experts in Berlin

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Hire experts who design clear data contracts, integrate REST and GraphQL APIs, and validate complex payloads across web and cloud systems. Get fast, precise matching with vetted, available freelancers suited to your JSON project.

Meet FRATCH Experts in Berlin, who have recently used JSON

Verified expert

Rüdiger S.

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Full-Stack Software Engineer / Consultant for Digitalization

Berlin
Rüdiger S.

Last position:

Full-Stack Software Engineer / Consultant for Digitalization at ARTEVENT

  • Designed, built, and launched an internal event planning web application used by over 100 department leads for a large event, despite having no dedicated testing phase.

  • Ensured smooth, failure-free operation during first production use, leading to the tool being adopted for future events.

  • Automated catering calculations and related workflows, significantly reducing email communication and manual computation effort for meal planning.

  • Managed deployment and hosting on a Linux server using Coolify, including application setup and runtime operations.

  • Hired and guided a communication designer on UX while independently owning all technical decisions and implementation.

Verified expert

Syed A.

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Senior Software Engineer

Berlin
Syed A.

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 F.

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

Berlin
Benjamin F.

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

Santhosh K.

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Freelance Software Engineer

Berlin
Santhosh K.

Last position:

Freelance Software Engineer at Zalando SE

  • Drive migration of enterprise authorization platform from Styra DAS to open-source OPA via Skipper (Zalando's Golang-based ingress proxy) integration
  • Optimise k8s resources and integrate native Prometheus metrics with OPA
  • Migrate from internal monitoring solution to Prometheus CRs + Dash0

Tech Stack: Java/Kotlin, Golang, Python, Spring Boot, AWS, Kubernetes, Docker, OpenTofu, Prometheus, Grafana

Verified expert

Sunish B.

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Technical Program Manager . Engineering Delivery & AI Systems

Teltow
Sunish B.

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

Imran A.

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Software Engineer II

Berlin
Imran A.

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

Giovanni L.

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Data and Solution Architect

Berlin
Giovanni L.

Last position:

Solution Architect at Nordea Bank

Consumer Cards Solution Architect

  • Provided architectural leadership in Consumer Cards Domain establishing best practices and improving architectural transparency and maintainability by designing a structured documentation framework to enable reverse engineering of legacy card systems.
  • Standardized architectural artefacts including BIAN Business Capabilities, UML diagrams in draw.io format (Use Case, Component, Sequence), naming conventions, document repository, design templates and blueprints, microservices.
  • Produced high-level and low-level designs aligned with enterprise architecture governance processes and artefact standards.
  • Provided architectural support to the Strategic Card Simplification Programme, focusing on card product migrations and application decommissioning across all countries. Agile environments (Scrum/SAFe).
  • Analysed and designed AI use cases in the architecture domain.

Project: Payment Card Industry Data Security Standards (PCI DSS) Strategic Programme

  • Analysed and documented existing data flows across card products and geographic regions to assess PCI DSS compliance.
  • Identified areas involving sensitive data at rest and data in motion requiring encryption or masking, ensuring adherence to PCI DSS requirements.
  • Collaborated with security, infrastructure, and application teams to align encryption strategies with regulatory and organizational policies.
  • Provided strategic advisory services on data strategy, data governance, data management, data quality, data architecture, data mesh, MEGA HOPEX, DAMA-DMBOK, event-driven architecture, end-to-end data flows and card product harmonization models.
  • Ensured solution design alignment with regulatory compliance (BCBS 239, DORA, GDPR) and internal policies.

Project: Denmark ATM Outsourcing Project

Objective: Outsource ATM operations and maintenance to a third-party provider while expanding the Denmark ATM fleet, with Nordea retaining ownership of ATMs and cash for the existing and extended infrastructure.

  • Led a cross-functional delivery team (project management, business analysis, and architecture) and documented the as-is ATM ecosystem architecture, including end-to-end data flows, integrations, and internal/external application interfaces.
  • Designed end-to-end processes for authorization, reconciliation, and settlement, aligning operating model, controls, and compliance requirements across Nordea and the outsourced service provider.
  • Produced high-level and low-level solution designs using standardized UML artefacts (Use Case, Component, and Sequence diagrams) to support vendor onboarding, integration planning, and implementation.
  • Ensured architectural alignment and decision-making across enterprise stakeholders and third-party providers, managing dependencies and interfaces in the context of the outsourcing initiative.
Verified expert

Hamza K.

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Academic Research Contributor in Health Sector (Volunteer)

Berlin
Hamza K.

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 S.

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Software Development for People

Berlin
Can S.

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

Vito B.

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AI Architect | LLM & Agentic AI for Manufacturing, MedTech, FinTech, SaaS, IoT

Berlin
Vito B.

Last position:

AI Architect & Engineer (Founder) at Arcate

  • Impact: Arcate turns scattered customer signals into ranked product decisions for B2B product teams. Every initiative is prioritized by revenue at risk. Every decision is traceable from customer quote to board slide. Built solo, deployed in production. Model validated at Kendall's tau = 0.924 vs. senior PM judgment across 60 simulation runs.

  • Skills: Artificial Intelligence, AI Agent, Large Language Model (LLM), RAG, Model Context Protocol (MCP), Agentic Workflows, Supabase, TypeScript, Deno, PHP, Stripe, PostgreSQL, Product Strategy, Positioning, GTM

  • Capabilities:

  • Signal Ingestion: Slack, Intercom, Gong, Salesforce, HubSpot. Signals classified by business severity to prioritize revenue-risk decisions.

  • Revenue Scoring: Fermi Leverage model. Initiatives ranked by customer ARR at risk, signal strength, and multi-account confirmation.

  • Roadmap Intelligence: Every bet traceable from raw customer signal to scored, board-ready decision.

  • Built:

  • MCP Server (v0.10.0): 12 tools, JSON-RPC 2.0, Supabase Edge Functions, SHA-256 API key authentication.

  • Scoring engine: Log-scaled ARR weighting, sqrt-dampened signal strength, multi-account signal confirmation.

  • Agentic Workflows: 18 automated pipelines covering release, provisioning, design QA, guard QA, and signal ingestion via Slack agents.

  • AI Skills: 7 codified skills including CEO Prioritizer, Design System Enforcer, MCP QA, Simulation Runner.

  • Automated QA: Browser-based screenshot validation of every screen against design tokens on every build.

  • Full SaaS: Auth, billing, media pipeline, design system. Deployed solo in production.

  • Stack: Supabase (Auth, DB, Edge Functions, Realtime), Stripe, Cloudinary, PHP, TypeScript, Deno

Verified expert

Mohsin H.

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Software Development Lead

Berlin
Mohsin H.

Last position:

BBM GenAI MiDAS program coordinator for Bosch eBike at Robert Bosch GmbH

The MiDAS program aims to integrate Generative AI across the entire BBM organization. My role is to enable the eBike division to adopt and leverage Generative AI by collaborating closely with the MiDAS team in India.

Management:

  • Enable the eBike division to adopt GenAI through tailored solutions.
  • Collaborate with the MiDAS team in India to design solutions for Generative AI use cases specific to the eBike division.
  • Coordinate with the eBike teams to integrate GenAI systems, tools, plugins, and services provided by the MiDAS team.
  • Plan roadmaps with eBike and MiDAS India team Product Managers for the delivery and integration of Generative AI solutions.
Verified expert

Mathias W.

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

Berlin
Mathias W.

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

Ursula R.

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Sabbatical with Training

Berlin
Ursula R.

Last position:

Sabbatical with Training at Own Sabbatical

Verified expert

Mario J.

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Architect / Developer

Berlin
Mario J.

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

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)

JSON experts in Berlin have 18 years of professional experience on average. It is 1 year less than in Germany, where the average stands at 19 years.

Position duration

2.2 years (Germany: 5.2 years)

JSON experts in Berlin stay in a single position for 2.2 years on average. It is 3 years less than in Germany, where the average stands at 5.2 years.

Positions per freelancer

12 (Germany: 14)

JSON experts in Berlin have completed 12 positions on average over the course of their careers. It is 2 fewer than in Germany, where the average stands at 14.

Top business areas

Information Technology, Product Development, Project Management

JSON experts in Berlin have gathered most of their hands-on project experience in Information Technology, Product Development, and Project Management.

Top industries

Information Technology, Professional Services, Banking and Finance

JSON experts in Berlin are most in demand in Information Technology, Professional Services, and Banking and Finance.

Certification focus areas

Information Technology, Product Development, Project Management

JSON experts in Berlin earn their certifications most often in Information Technology, Product Development, and Project Management.

Bachelor's degree or higher

95% (Germany: 89%)

95% of JSON experts in Berlin hold at least a Bachelor's degree. It is 6% higher than in Germany, where the rate stands at 89%.

Master's degree or higher

63% (Germany: 56%)

63% of JSON experts in Berlin hold at least a Master's degree. It is 7% higher than in Germany, where the rate stands at 56%.

Doctorate

13% (Germany: 10%)

13% of JSON experts in Berlin have a doctorate (PhD). It is 3% higher than in Germany, where the rate stands at 10%.

Certifications per freelancer

1 (Germany: 2)

JSON experts in Berlin hold 1 professional certification on average. It is 1 fewer than in Germany, where the average stands at 2.

Most common languages

English, German, Spanish

JSON experts in Berlin most often speak English, German, and Spanish.

Speak two or more languages

96% (Germany: 98%)

96% of JSON experts in Berlin speak two or more languages. It is 2% lower than in Germany, where the rate stands at 98%.

Based on our profile pool as of 19 Sep 2026.

Daily rate distribution

0 10 20 30 40
2 of the JSON experts in Berlin charge less than €400 per day.
23 of the JSON experts in Berlin charge between €400 and €800 per day.
16 of the JSON experts in Berlin charge between €800 and €1200 per day.
4 of the JSON experts in Berlin charge €1200 or more per day.
<€400 €400-​800 €800-​1200 €1200+

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. 739 €
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 752 €
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 19 Sep 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 (98%)
  • Professional Services (42%)
  • Banking and Finance (40%)
  • Media and Entertainment (38%)
  • Manufacturing (35%)
  • Automotive (33%)
  • Retail (33%)
  • Education (29%)

Please note that freelancers can work across multiple industries, so percentages overlap.

About the technology

Data format

JSON, short for JavaScript Object Notation, is a text-based format for exchanging structured data. Its objects, arrays, strings, numbers, booleans and null values are easy for software to process and people to inspect. It is widely used between browsers, applications, services and data tools.

Where it runs

JSON is a core part of REST APIs, GraphQL responses, event payloads and configuration files. It supports web and mobile applications, serverless functions, microservices, integrations and data pipelines. Companies in Berlin use it across digital products, commerce, finance, logistics and connected services.

Ecosystem and tooling

Strong JSON specialists understand the systems around the format, not only its syntax. Their work may include:

  • Designing OpenAPI schemas and stable API contracts
  • Validating payloads with JSON Schema and automated tests
  • Transforming JSON with JavaScript, Python, Java or jq
  • Connecting REST, GraphQL, queues and cloud services

They also work with serialization libraries, API gateways, documentation tools, version control and observability systems. Good tooling makes malformed data easier to detect before it reaches production.

When expertise helps

Companies bring in freelance JSON expertise when an API contract is unclear, integrations fail across teams or a legacy format needs careful migration. Specialists can map inconsistent payloads, define naming conventions, improve validation and document the data exchanged by each service. They can also review an existing interface before a larger product change.

Quality signals

A capable professional treats JSON as part of a broader data contract. They consider compatibility, optional fields, error responses, encoding, security and the effect of schema changes on consumers. They write readable examples, test edge cases and explain trade-offs to product, design and engineering teams.

For Berlin teams, remote collaboration can work well when documentation, review routines and ownership are clear. On-site workshops may help when several local teams must agree on shared API models or integration rules.

Project outcomes

Typical deliverables include an API specification, JSON Schema definitions, transformation logic, validation rules, integration tests and technical documentation. A specialist may also provide migration plans, sample payloads, contract tests or a review of production data flows. The right scope depends on whether JSON is used for a new interface, an integration repair or a wider platform redesign.

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Frequently asked questions

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

JSON is mainly used to exchange structured data between applications, browsers, services and external systems. Companies use it for API responses, requests, configuration files, event messages and data transformation. Its simple text format makes it practical for both machine processing and human review.

JSON is usually more compact and maps naturally to objects and arrays used in many programming languages. XML offers mature document features, namespaces and attribute support, which can suit document-heavy or highly formal integrations. The right choice depends on existing systems, validation needs and the required data model.

A strong JSON specialist should understand HTTP, REST, GraphQL, authentication and API versioning. Useful adjacent skills include JSON Schema, OpenAPI, JavaScript, Python, Java, database mapping, automated testing and cloud integration. Experience with logging and observability also helps when payloads fail across service boundaries.

The required background depends on the scope, not on JSON alone. A small payload cleanup may need focused API and validation knowledge, while a distributed integration requires experience with contracts, backward compatibility, security and production troubleshooting. Ask for examples that resemble the systems, data volume and risk of your project.

JSON work is often well suited to remote collaboration because schemas, examples, tests and API specifications can be reviewed asynchronously. Berlin teams should establish clear ownership, shared documentation and regular technical reviews. On-site sessions can still be useful when several stakeholders need to agree on a common data contract.

Review whether the JSON design is consistent, documented and validated against realistic edge cases. Check naming, optional fields, error handling, compatibility rules and the clarity of sample payloads. A quality specialist can explain why the contract will remain usable for current and future consumers.

JSON Schema is valuable when an API or event format needs explicit validation and shared documentation. It can define required properties, data types, allowed values and nested structures for automated checks. It does not replace good API design, so teams should also define versioning and compatibility practices.

Before working with JSON, clarify who produces and consumes each payload, which interfaces are already in production and how changes are released. Ask about authentication, error formats, sample data, validation rules and compatibility expectations. These details reveal whether the assignment is a small transformation task or a wider integration responsibility.

The average hourly rate of freelancers in Berlin, Germany who have used JSON in their recent projects is 92 €, which corresponds to a daily rate of about 739 € based on an 8-hour working day.

Of the freelancers in Berlin, Germany who have used JSON in their recent projects, 95% hold at least a Bachelor's degree, 63% hold at least a Master's degree, and 13% 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 2.2 years.

The most common languages among freelancers in Berlin, Germany who have used JSON in their recent projects are English (96%), German (94%), and Spanish (13%).

The most common industries among freelancers in Berlin, Germany who have used JSON in their recent projects are Information Technology (98%), Professional Services (42%), and Banking and Finance (40%).

The most common business areas among freelancers in Berlin, Germany who have used JSON in their recent projects are Information Technology (96%), Product Development (92%), and Project Management (54%).

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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