Senior C++ Software Engineer (FIX, Client Connectivity)

Senior C++ Software Engineer (FIX, Client Connectivity) About the Offer We are currently looking for a Senior C++ Software Engineer to join the team of one of the world's leading global investment banks. The project is delivered together with a large international IT services company. For this role, Optiveum is the recruitment and contracting party, which means you will sign the cooperation agreement directly with us. You will work on the bank's global client connectivity and equity trading systems, as part of a multi-year initiative to modernise its connectivity platforms. The role is strongly hands-on: about 80–90% of your time goes to development work. Key Details: Rate: 120–130 PLN/h (B2B), depending on experience Work Model: Hybrid, 3 days per week from the client's office (non-negotiable), full-time Location: Kraków (candidates must live in or within commuting distance of Kraków) Start: December 2026 Responsibilities: Work in a global team to define architectural solutions and solve complex technical challenges Contribute to the modernisation of existing client connectivity platforms, improving their scalability, reliability and maintainability Deliver technical enhancements: performance improvements, client-specific functionality and compliance with changing market regulations Help transform the team's delivery ecosystem by adopting DevOps practices and advancing CI/CD Collaborate with business analysts, developers and business stakeholders across regions Hands-on development: coding, technical design, configuration management, release execution and post-implementation support Requirements: 5–7 years of hands-on C++ experience: multi-threading, data structures, STL, casting, templates, pointers, socket programming and algorithms Programming in Linux/Unix environments Development experience in a financial environment on order management systems, the FIX protocol and order-state handling (essential) Experience building high-performance, high-availability, high-throughput, low-latency, transaction-oriented distributed systems Strong knowledge of the equity trading environment, ideally in a multi-regional setting Excellent English communication skills (business and technical) Polish or EU citizenship, or a permanent residence / work permit valid for at least 12 months Nice to Have: Prior experience working on a client connectivity system Java experience: Core Java, Collections and Reflection Level 3 (development) support in a pressurised production environment Recruitment Process: Technical tasks are done live: please have your environment, tools and language/framework versions set up and tested beforehand. The use of AI tools, coding assistants or code generators during interviews is not allowed The selected candidate will go through a background check, so the dates and employers in your CV must be accurate Your name in the application and CV must match your official ID document exactly (Polish citizens: please include all first names) Candidates who took part in a recruitment process for this IT services partner or this bank in the last 12 months cannot be considered