C Experts in Cologne
for reliable systems software, matched in minutes with vetted freelance professionalsHire experts who build embedded software, operating-system components and high-performance services with C, POSIX APIs and cross-compilation toolchains. FRATCH finds a precise match quickly from 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)
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
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
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.
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.
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
Kai B.
Last position:
Freelance CPQ Consultant (Full-Time) at Freelance CPQ Consultant
- Independent CPQ consulting for a portfolio of industrial manufacturers, including Scheidt & Bachmann, Trützschler Group SE, and Weiss Klimatechnik GmbH (Schunk Group)
- Full project coverage: requirements analysis, concept, system design, implementation, testing, and international go-live support
- Deep integration work with SAP ECC (material master replication, SD document creation, material creation, general APICONNECT and other web service interfaces)
- Process consulting: analysis and optimization of internal quoting processes for sales and management
- Knowledge transfer/coaching and pair programming to strengthen internal team skills
Andreas W.
Last position:
Freelancer at Infrafibre Networks GmbH
- Assessing the current status (planning stage / rollout status) of the so-called inter-polygon routes
- Creating an end-to-end project plan for the individual routes, considering active and passive components and tasks
- Monitoring and controlling the implementation of the plan
- Optimizing the chosen network architecture
- Creating network and splice diagrams
Anup R.
Last position:
Cybersecurity Expert at Autosec Innovation Private Limited
- Technically leading an international team on Aurix 2nd Generation (TC3XX) multicore AUTOSAR architecture, supporting various OEM programs.
- Responsible for customer security requirements analysis, asset identification, and deriving TARA and security concepts at the system level.
- Conducted system and software/hardware vulnerability analysis and implemented cybersecurity solutions using Crypto, HSM, MPU, BSW, OS, and ISO 21434-compliant stacks provided by Vector.
- Led architecture discussions with OEMs and suppliers to align cybersecurity strategies with vehicle platforms.
- Contributed to the design and integration and testing of SecOC, UDS authentication and wireless interfaces like WiFi, Bluetooth, V2X ensuring secure and seamless vehicle access.
- Addressed security challenges such as relay attacks, replay attacks, and credential spoofing through advanced threat modeling and mitigation strategies.
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
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
2.3 years (Germany: 3.1 years)
Positions per freelancer
15 (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
85% (Germany: 90%)
Master's degree or higher
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 19 Sep 2026.
Daily rate distribution
The chart shows how the daily rates of freelancers in this technology in Cologne 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 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 19 Sep 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 (53%)
- Banking and Finance (47%)
- Automotive (43%)
- Transportation (43%)
- Healthcare (40%)
- Government and Administration (37%)
- Telecommunication (37%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
What C is
C is a compiled, general-purpose programming language designed for direct control over memory, data layout and hardware interfaces. It is used where predictable performance, small runtimes and portability matter, from firmware and operating-system components to networking software. The language remains closely tied to POSIX and ISO C standards.
Where it runs
C powers microcontroller firmware, device drivers, kernels, databases, telecommunications software and command-line tools. It also forms the foundation of major language runtimes and libraries. In Cologne and across Germany, specialists may support industrial electronics, automotive systems, logistics infrastructure and other products that require dependable native software.
- Embedded control and firmware
- Linux system components and drivers
- Network services and protocol implementations
- Performance-critical libraries
Ecosystem and tooling
A C project commonly combines GCC or Clang with Make, CMake, linker scripts and a debugger such as GDB. Professionals work with Git, static analysis, sanitizers, unit testing frameworks and continuous integration. Depending on the target, they may also use vendor SDKs, RTOS environments, POSIX interfaces and cross-compilers for ARM or other processor families.
When expertise matters
Companies bring in freelance C specialists when a product needs native performance, hardware access or a stable maintenance path. They can modernize an older codebase, port software to a new processor, investigate memory corruption or prepare firmware for production. Clear interfaces and disciplined ownership are especially important when several teams share low-level libraries.
- Diagnose crashes, leaks and race conditions
- Port code across operating systems or architectures
- Improve build, test and release workflows
- Review safety, security and resource usage
Strong professional practice
Reliable C work starts with careful ownership of memory, buffers, pointers and error paths. Strong professionals understand undefined behavior, integer boundaries, concurrency and the effects of compiler settings. They write readable interfaces, document assumptions and use tests, static analysis and debugging evidence instead of relying on intuition.
Working with a specialist
Before starting, define the target hardware or operating system, compiler constraints, interfaces and acceptance tests. Share build instructions, diagnostic data and representative workloads so the specialist can reproduce problems quickly. Remote collaboration works well when repositories, test hardware and logs are accessible; on-site work in Cologne can help when physical devices or lab equipment are central to delivery. German or English communication should match the wider project team.
Frequently asked questions
What clients ask us most about C — answered in short.
C is commonly used for embedded firmware, operating-system components, device drivers, networking software and performance-sensitive libraries. It is a strong choice when software must interact closely with hardware or run with limited memory and processing resources.
C offers a small language core, broad portability and direct control over memory and data layout. C++ adds abstraction and object-oriented features, while Rust provides compile-time ownership checks; the right choice depends on existing code, toolchains, safety requirements and runtime constraints.
A strong C specialist often works with Linux, POSIX, Git, CMake, GCC or Clang and GDB. Embedded assignments may also require RTOS concepts, microcontroller peripherals, communication protocols, cross-compilation and hardware debugging.
The need depends on the risk and depth of the work, not simply on the size of the codebase. A specialist handling firmware, concurrency, safety-sensitive behavior or difficult memory faults should demonstrate relevant shipped work and explain the decisions behind it.
C projects can often be delivered remotely when source code, build environments, logs and test access are available. On-site collaboration in Cologne becomes more useful when the assignment involves physical prototypes, lab equipment, manufacturing tests or close coordination with hardware teams.
Look for evidence of production work involving memory ownership, error handling, testing and debugging rather than sample code alone. Ask how the specialist diagnosed a fault, managed interfaces and verified behavior across compilers, operating systems or target hardware.
C remains suitable for legacy maintenance when the specialist can preserve established behavior while improving tests, documentation and build reproducibility. Good work separates safe refactoring from compatibility-sensitive changes and uses tools to expose undefined behavior before modifying critical paths.
Maintainable C code has clear ownership rules, small interfaces, consistent error handling and documented assumptions about data and concurrency. Automated tests, compiler warnings, static analysis and reproducible builds make later changes safer and help teams review specialist work objectively.
The average hourly rate of freelancers in Cologne, Germany who have used C in their recent projects is 97 €, which corresponds to a daily rate of about 774 € based on an 8-hour working day.
Of the freelancers in Cologne, Germany who have used C in their recent projects, 85% hold at least a Bachelor's degree, 65% 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 2.3 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 (27%).
The most common industries among freelancers in Cologne, Germany who have used C in their recent projects are Information Technology (90%), Manufacturing (53%), and Banking and Finance (47%).
The most common business areas among freelancers in Cologne, Germany who have used C in their recent projects are Information Technology (100%), Product Development (90%), and Quality Assurance (53%).
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.
Berlin 
Hamburg 
Munich 
Frankfurt 
Stuttgart 
Dusseldorf 
Leipzig 
Dortmund 
Essen 
Hanover 
Nuremberg Request a free demo
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Philipp Thomaschewski
FRATCH CEO
