Senior C Developer

Senior C Developer (Legacy Systems / Performance Optimization)
Remote | Full-time | B2B Contract |

We are looking for an experienced Senior C Developer to join a project focused on optimizing the performance of a legacy data processing system.
The existing platform processes large volumes of data through ETL pipelines and loads the results into a relational database (Db2). As data volumes increase, the system experiences performance degradation.
Your main responsibility will be to identify performance bottlenecks, optimize existing C code, and improve the scalability and efficiency of data processing.
We are also open to experienced C++ developers with strong C knowledge who are comfortable working primarily with C.

Responsibilities
Analyze and optimize existing C code in a legacy production environment.
Identify and resolve performance bottlenecks in data processing and ETL workflows.
Improve application performance and scalability as data volumes increase.
Work with relational databases and SQL queries.
Optimize multithreaded and parallel processing using Intel OpenMP and related technologies.
Investigate CPU, memory, and database performance issues.
Maintain and improve existing system components while ensuring stability.
Use AI-assisted development tools, including Claude, in daily engineering workflows.
Collaborate with an international engineering team.

Requirements
Strong commercial experience with C programming.
Solid knowledge of C++, with readiness to work primarily in C, is also acceptable.
Experience with performance optimization, profiling, and debugging.
Hands-on experience maintaining or modernizing legacy systems.
Good understanding of multithreading, concurrency, and parallel programming.
Experience with Intel OpenMP or comparable parallel programming technologies.
Strong SQL skills and experience with relational databases.
Understanding of memory management and low-level application performance.
Experience using AI coding assistants or AI-assisted development workflows.
English B2+/C1 — confident technical communication.

Nice to Have
Experience with IBM Db2.
Knowledge of Embedded SQL / SQL embedded in C.
Experience optimizing ETL or large-scale data processing systems.
Experience with high-volume batch processing.
Experience with performance-sensitive enterprise applications.

Project Details
Engagement: Full-time
Duration: Several months
Location: Remote, excluding Russia and Belarus
Rate: Up to $18/hour
Start: To be discussed
Why Join?
Work on challenging performance engineering problems.
Optimize a production system processing growing volumes of data.
Apply your expertise in C, concurrency, SQL, and low-level optimization.
Work in an engineering environment using modern AI development tools.
Interested? Apply with your CV