Senior Python Developer – NumPy & Performance Optimization (m/f/d)

Position Description

We’re establishing a brand-new technology and innovation hub in Sofia – and you can be part of it from day one.

Here, you won’t just be shaping our services for German clients; you’ll also help us build a strong presence in the Bulgarian market. You’ll collaborate closely with our teams in Germany, bring in your ideas, and influence the tools, processes, and culture of our new Sofia location from the ground up.

In short: We’re blending the energy of a fresh start with the reliability of a global player. If you’re excited about building something new both locally and internationally, this is the place to make your mark. Apply now and be part of our success story in Sofia! #BePartofourStory Let‘s #GrowTogetherNow

Your future duties and responsibilities:

The developer will focus on optimizing the performance of an existing Python solution, identifying bottlenecks and improving runtime for compute-intensive processes. They will also work on data analysis and validation of planning models and contribute to the development of a dashboard-based Planning Tool. The role includes building data validation workflows, status and notification features, and visualizations of planning results.

• Optimize Python/NumPy workloads and improve runtime performance.
• Identify and resolve Python performance bottlenecks.
• Analyze and validate data and statistical models.
• Develop dashboard and planning tool functionality.
• Build automated data processing and validation workflows.
• Develop and maintain automated tests.

Required qualifications to be successful in this role:

• 5+ years of professional Python development experience.
• Strong hands-on experience with Python and NumPy.
• Experience with Numba (njit) and performance optimization.
• Good understanding of CPython performance and interpreter overhead.
• Strong experience with pytest, Git and pandas.
• Knowledge of data analysis and visualization.
• Experience with Dash, Streamlit or similar frameworks is an advantage.
• Experience with Ray, Optuna or similar tools is beneficial.
• Strong English communication skills.

What We Offer:

• Team Culture: You’ll find colleagues here who make collaboration enjoyable. We interact openly, use first names across all levels, and don’t think in hierarchies or silos.
• Contract & Working Time: Permanent, full-time contract with a standard 8-hour workday.
• Flexible Work Setup: Enjoy the best of both worlds with our hybrid work model – combining office presence in Sofia with remote work from home.
• Working Hours: Flexible working hours tailored to project needs and client requirements.
• Leave Policy: 25 days of paid vacation + 1 day for your Birthday.
• Premium supplementary health insurance package: Including coverage for prescription glasses, reimbursement of medical expenses, and dental care.
• Volunteer Opportunities: Make a positive impact with 8 hours of paid leave for voluntary work.
• Career Development: Benefit from clear career progression paths and opportunities to grow within the company.
• Continuous Learning: Access our internal learning platform, CGI Academia, to shape your skills based on your interests. Learn up to 9 languages via goFLUENT.
• Referral Rewards: Extend your network – refer friends and earn bonuses through our rewarded referral program.
• Health & Wellbeing: Access our Health and Wellbeing Portal for resources that support your physical and mental health.
• Multisport Benefit: Аvailable at a preferential price for access to various sports and wellness facilities.
• Office Environment: Work in a state-of-the-art co-working space in Sofia, with complimentary coffee, tea, and water to keep you refreshed throughout the day.

Together, as owners, let’s turn meaningful insights into action.

Life at CGI is rooted in ownership, teamwork, respect and belonging. Here, you’ll reach your full potential because…

You are invited to be an owner from day 1 as we work together to bring our Dream to life. That’s why we call ourselves CGI Partners rather than employees. We benefit from our collective success and actively shape our company’s strategy and direction.

Your work creates value. You’ll develop innovative solutions and build relationships with teammates and clients while accessing global capabilities to scale your ideas, embrace new opportunities, and benefit from expansive industry and technology expertise.

You’ll shape your career by joining a company built to grow and last. You’ll be supported by leaders who care about your health and well-being and provide you with opportunities to deepen your skills and broaden your horizons.

That same commitment to fairness extends to how we use technology. To support our recruitment team, AI tools may be used to help assess applications though they never replace human judgement. All hiring decisions remain entirely in the hands of our recruitment professionals.

Come join our team—one of the largest IT and business consulting services firms in the world.