C Experts in Cologne
, matched in minutes with vetted and available freelancersHire experts who write performance-critical software, build embedded firmware and integrate operating-system interfaces in C, with experience across POSIX, Linux, microcontrollers and build tooling. FRATCH finds a precise match quickly among vetted, available freelancers.
Meet FRATCH Experts in Cologne, who have recently used C
Jens R.
Last position:
Platform Architect & Senior Developer at Direct client, industrial measurement technology, medium-sized company
- Technical leadership across hardware, firmware, and software teams; scope: hardware/firmware team (4 people) and leadership group (5 people)
- Consolidated and documented a product family that had grown over more than 15 years and aligned it with CRA compliance — from the bare-metal I/O module to the cloud interface.
- Provided the most important customer product with the essential requirements and architecture documentation within two months — for a firmware landscape that had grown over more than 15 years. It now supports the customer’s modernization strategy.
- Established a monthly reporting line to the supervisory board and executive board within three months: nine meetings since 12/2025. The report itself is versioned and built from the CI pipeline; it is based on automatically collected activity and release data instead of assessments.
- Built a container-based CI/CD infrastructure from scratch: cross-compilation, host tests, and documentation builds in one continuous pipeline.
- Introduced declarative QA gates for DevOps and development artifacts — from the start using lefthook instead of pre-commit, executed in a dedicated container image.
Technologies used: arc42, req42, tpo42, docToolchain, PlantUML, ArchiMate, C4 model, ADR, C, C++ (GTest), CMake, Bare Metal (ARM Cortex-M3/M7), OCI containers, Jenkins, lefthook, Prometheus, Grafana, SBOM, CRA, OPC, SCADA, PLC integration, IPv6 migration, Zero Trust, Sociocracy 3.0, Cynefin
Burhan D.
Last position:
Enterprise Architect & Solution Architect at DB Netz AG
With project PRIZMA, DB will modernize its infrastructure on the one hand, and develop a fail-safe IT landscape on the other hand, which can be restored quickly and securely in case of a disaster.
- Capture current architectures of existing systems as well as methodical consulting and development of target architectures
- Deepen and maintain the building plan / target IT landscape
- Implement technical architecture concepts & architecture descriptions
- Implement migration concepts for updating and further developing the platform and information systems
- Assess submitted improvement suggestions as part of the project
- Capability management: identify capability gaps, develop target visions, and support transformation planning within the enterprise architecture.
- Create a compatibility matrix of the components in use and compare dependencies of specific versions
- Create an IT concept for extending the platform with the following topics: hardware and software requirements, security, licensing, high availability, load balancing, backup & recovery, update strategy, monitoring integration, etc.
- Coordinate with business architects as well as technical architects from the cross-functional architecture area of the PRISMA program for the topics (backup, Active Directory, monitoring, Citrix, and business applications ...)
- Status meetings and alignment of project planning with the Release Train Engineer / Project Manager
- Advise the Release Train Engineer / Project Manager in identifying project risks
- Advise the System Architect Engineers in steering the implementation of the concept
- Implement the IT concept
- Document the infrastructure
Label: MS Project, LINUX, Windows, ORACLE, Java, REST, SharePoint, Microsoft Exchange, UML, Enterprise Architect, BPMN, AZURE, AWS, V-MODEL, Micro Service, VisualStudio, SAP S/4HANA, SCRUM(SAFE), ESB (TIBCO), Python, Innovator, LeanIX (TOGAF), Ansible, Ansible Tower, Ansible Automation, ROBOT, SpringBoot
Achim R.
Last position:
Project and Program Manager, PMO Lead at Freelancer / Interim Manager
Successful delivery of projects on behalf of customers:
-> 2023 – present: Project management for the consolidation of sites/data centers for a large telecommunications provider (infrastructure project, customer: Telefonica)
Opening and preparing new sites
Application migrations
Decommissioning and handover of old sites
-> 2021 – 2022: IT multi-project management for a large car leasing company (customer: Athlon)
Migration of applications to the cloud and to another data center
Additional projects to expand and optimize the application landscape
-> 2021: Project management for the development of a platform providing internet access on aircraft operated by various airlines (customer: m3Connect/German Telekom)
-> 2017-2020: Responsible management of an IP network consolidation (infrastructure project, customer: Cisco/Vodafone) at a large telecommunications provider
Planning and coordination of migrations and their rollout
Team leadership and integration of different teams (network operators, hardware and service providers)
Michael K.
Last position:
Enterprise Architect, Lead Architect of the transformation program and coach at Swiss Ministry
- Development of the overall architecture
- Support for the respective workstreams in developing architectures in the areas of infrastructure, data centers, security, and network topology
- Management of the architect pool
- Support for program management in setting up the transformation project based on agile methods
- Consideration of regulatory requirements for IT projects in the federal administration
Andreas B.
Last position:
Senior Software Developer at ELIONOVA AG
- Created an application to control measurement hardware with a Tauri application using React.JS and TypeScript on Raspberry Pi
- Developed a cloud application for storing and analyzing measurement results using Spring Boot and React.JS
- Built a Tauri application for printing ZPL labels on Windows
- Technologies: Java, JavaScript, Tauri, Rust, React.JS, AWS, Kubernetes, Docker, GitLab CI/CD, REST API (JSON), Maven, CI/CD, PostgreSQL
Andreas W.
Last position:
Freelancer at Infrafibre Networks GmbH
- Determining the current status (planning status / expansion status) of the so-called interpolygon routes
- Preparing an end-to-end project plan for the individual routes, taking active and passive components and activities into account
- Monitoring and controlling plan implementation
- Optimizing the selected network architecture
- Creating network and splice plans
Alexander K.
Last position:
Software Tester at Buhl Tax Service GmbH
- AI-assisted creation of test cases and test data
- Creation of test cases based on requirements
- Execution of manual tests
- Defect documentation, retesting and tracking
Technologies & Tools: SCRUM, Jira, Confluence, Zephyr Scale
Muhammad J.
Last position:
Embedded Linux Intern – IoT Sensor Prototype Development at DHL
- Built a modular C++ 20 embedded Linux acquisition system on a Raspberry Pi, synchronizing IMU and dual-camera data streams to sub-millisecond accuracy.
- Integrated retro-reflective and contrast sensors to trigger acquisition and detect gaps between sorter rails.
- Implemented SPI & I2C sensor communication, GPIO interrupt handling with libgpiod, and CSV & JSON output.
- Designed a multi-threaded acquisition pipeline and an SPSC queue between acquisition and writer threads.
- Built a Python/HTML/CSS based web-server and validated the prototype in a DHL warehouse for defect detection.
- Documented software behavior, configuration, and results for maintainable handover and further development.
Dmitriy D.
Last position:
Freelance Senior Data Scientist at Merck KgaA
- AWS
- Genedata Profiler
- Data Lake
- APIs
- Rstudio
- GitLab
- Python
- R
- Data acquisition, integration, and simulation
- Multiplex immunofluorescence
- Copy-number variation calling
- HLA typing and loss-of-heterozygosity analysis
- RNA expression analysis
Jeanne Y.
Last position:
Process Engineering Intern at Procter & Gamble
- Independently initiated and deployed automated validation workflows using Python, cutting manual processing by 58% and improving efficiency
- Developed a machine learning model for synthetic defect generation, reducing downtime and production costs; deployed locally and via Databricks and Azure AI Factory
- Utilized a small dataset of image data from the production lines and extended this dataset with training on models like cycleGAN and pix2pix
- Built and optimized the Linux-based development environment for training 3D models; maintained reproducibility via GitHub
- Presented technical insights to cross-functional teams (engineers, QA, project managers), ensuring alignment of ML solutions with operational needs
Stefan M.
Last position:
Bundesrechtsanwaltskammer
- Design, planning and execution of complex acceptance tests for a document exchange platform for the German justice authorities.
- Validation of decrypted and certificate-based message exchange via web platform, mobile app, and Java API.
- Documentation of test cases, execution steps, and test results.
- Technologies: Windows 11/10, Ubuntu, iOS, Android, Bash for Windows, Java 17, IntelliJ, Git, Jira, Confluence, Citrix Server, xJustiz standard implementation, specific justice software.
Christoph S.
Last position:
Test Manager at Logistics
- Coordination and planning, execution, documentation, and analysis of test cases
- Development of test concepts considering best practices (e.g., test pyramid) with a focus on reliable, automatable test runs
- Implementation and maintenance of test cases according to the test concepts
- Technologies: Citrix Workspace, Shopify, Jira, Xray, MS Teams, MS SharePoint, Confluence, MS Office 365
Allal K.
Last position:
Java Senior Full Stack Developer at Insurance ÖRAG
- Further development of a policy administration system (contract/claims) for the legal expenses insurer ÖRAG.
- My role: Senior Software Developer.
- The team consists of 12 developers.
- Technologies used: Java 8/21, Java EE, Quarkus, WebLogic, JPA, RabbitMQ, JTA, CI, CD, Jenkins, DB2, Maven, Jenkins, GIT (bitbucket) later GitLab, Junit, Elasticsearch, Mockito, Jira, SonarQube, Scrum, React, Workflow
- Migration and modernization of legacy systems: rewrote C and C++ code in Java to improve maintainability, scalability, and performance. Refactored Python into Java, including optimization and integration into modern architectures.
- Study on the use of AI (Codex) for implementing a Java feature. The goal is to compare the time spent and productivity of AI-supported development with a classic implementation by a developer. The results should show how strongly the use of AI affects development time and efficiency.
- Development of the following tariff calculators for the years 2024/2026: private, companies, doctors, farmers, owner-occupied G + H, landlords, traffic, club, top managers, sales representatives, special criminal law, savings bank, municipal, BayGT, doctors, Dehoga
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
Andreas E.
Last position:
Consultant at Iteratec GmbH
Discover over 15,000 top freelancers
Statistics of experts using C
Aggregated from the professional profiles of matched freelancers.
Experience
22 years (Germany: 21 years)
Position duration
2.4 years (Germany: 3.1 years)
Positions per freelancer
16 (Germany: 13)
Top business areas
Information Technology, Product Development, Quality Assurance
Top industries
Information Technology, Manufacturing, Banking and Finance
Certification focus areas
Information Technology, Project Management, Quality Assurance
Bachelor's degree or higher
84% (Germany: 90%)
Master's degree or higher
64% (Germany: 65%)
Doctorate
8% (Germany: 11%)
Certifications per freelancer
2
Most common languages
German, English, French
Speak two or more languages
97% (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 Cologne 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 Cologne using C
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.
C 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 (90%)
- Manufacturing (52%)
- Banking and Finance (45%)
- Transportation (45%)
- Automotive (41%)
- Healthcare (38%)
- Government and Administration (38%)
- Telecommunication (38%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
Systems Programming
C is a compiled, procedural language used where direct control of memory, hardware and execution matters. It remains central to operating-system components, device firmware, networking software, databases, compilers and high-performance libraries. Its small runtime footprint makes it suitable for constrained and safety-sensitive environments.
Embedded and Native Software
C specialists deliver firmware for microcontrollers, drivers, bootloaders and real-time control systems. They also build native libraries, command-line tools and services that interact closely with Linux, Unix or Windows. In Cologne, this expertise can support industrial equipment, mobility products, medical devices and connected hardware.
Ecosystem and Tooling
The work extends beyond the language itself. Strong professionals use GCC or Clang, Make, CMake, linker scripts, debuggers and profilers, while working with POSIX APIs, sockets, threads and cross-compilation toolchains. Common environments include Linux, RTOS platforms and vendor SDKs for embedded targets.
- Design interfaces between C modules and hardware
- Diagnose memory, concurrency and performance faults
- Maintain portable code across compilers and operating systems
- Connect C libraries with C++, Python or other application layers
When to Bring in Expertise
Companies often need freelance C expertise during firmware releases, platform migrations or difficult production investigations. A specialist can take ownership of an unfamiliar codebase, replace unsafe interfaces, improve test coverage or prepare a legacy component for new hardware. This is useful when internal teams need focused capability without interrupting product delivery.
What Strong Professionals Deliver
Quality starts with clear ownership of memory, lifetimes, data representation and error paths. Experienced C professionals write readable interfaces, limit undefined behavior and use static analysis, sanitizers, unit tests and hardware-in-the-loop checks where appropriate. They document build assumptions and explain trade-offs clearly to teams working in English or German, remotely or on site.
Choosing the Right Specialist
Match the specialist to the target environment rather than to the language name alone. Firmware work may require interrupts, peripherals and real-time constraints, while Linux systems work may depend on processes, networking and kernel interfaces. Review comparable deliverables, debugging methods, test discipline and familiarity with the project’s compiler, build system and deployment process.
Frequently asked questions
What clients ask us most about C — answered in short.
C is used for operating-system components, embedded firmware, device drivers, networking tools, databases and native libraries. It is a strong choice when predictable performance, small binaries and direct hardware access matter.
C offers a smaller language surface and direct control with fewer built-in abstractions. C++ can provide richer type systems and object-oriented or generic structures, so the choice depends on runtime constraints, team skills, existing interfaces and the project’s maintenance needs.
A strong C specialist may also work with C++, assembly, Linux, POSIX, networking, RTOS platforms and hardware debugging. Useful supporting skills include CMake or Make, Git, static analysis, cross-compilation and automated testing.
C work can require very different depth depending on the system. A contained library change may suit a specialist who can follow established interfaces, while firmware, driver or concurrency work calls for proven debugging practice and a careful understanding of hardware and failure modes.
C projects can often be handled remotely when source control, build environments, test hardware and logs are accessible. On-site work may add value for hardware bring-up, lab testing or restricted equipment, while clear communication in English or German helps distributed teams work efficiently.
Ask how the C specialist handles ownership, bounds checking, error paths, concurrency and portability. Review test strategy, use of static analysis and sanitizers, debugging records and the clarity of interfaces rather than judging code only by whether it compiles.
ANSI C refers to standardized versions of the language, while modern C usually means a project’s selected ISO C standard and its compiler-supported features. A specialist should confirm the required standard, compiler extensions, portability targets and safety rules before changing the code.
C is frequently used as a fast, portable core behind higher-level software. C++ may consume its libraries directly, while Python and other languages can call them through bindings; a capable specialist understands ABI boundaries, memory ownership and build integration across those layers.
The average hourly rate of freelancers in Cologne, Germany who have used C in their recent projects is 96 €, which corresponds to a daily rate of about 765 € based on an 8-hour working day.
Of the freelancers in Cologne, Germany who have used C in their recent projects, 84% hold at least a Bachelor's degree, 64% hold at least a Master's degree, and 8% hold a doctorate.
On average, freelancers in Cologne, Germany who have used C in their recent projects have 22 years of professional experience, with a single engagement typically lasting around 2.4 years.
The most common languages among freelancers in Cologne, Germany who have used C in their recent projects are German (100%), English (97%), and French (28%).
The most common industries among freelancers in Cologne, Germany who have used C in their recent projects are Information Technology (90%), Manufacturing (52%), and Banking and Finance (45%).
The most common business areas among freelancers in Cologne, Germany who have used C in their recent projects are Information Technology (100%), Product Development (93%), and Quality Assurance (52%).
Main locations of FRATCH Experts, who have recently used C
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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Stuttgart 
Dusseldorf 
Leipzig 
Dortmund 
Essen 
Bremen 
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Philipp Thomaschewski
FRATCH CEO
