Senior Python Developer

Who we are!

At Levi9, we are passionate about what we do. We love our work and together in a team, we are smarter and stronger. We are looking for skilled team players who make change happen. Are you one of these players?

About the project

We develop a technology platform for large international companies in the CPG (Consumer Packaged Goods) industry. It helps companies improve sales planning, forecast demand, manage commercial processes, and make better decisions based on large volumes of data.

The platform processes large datasets and uses Machine Learning and AI to improve forecasting, automate processes, and help users access relevant insights faster.

About the role

You will join the engineering team responsible for developing and evolving key components of the client's platform.

The main focus of the role is backend development, large-scale data processing, performance, and scalability. You will work on both new functionality and the improvement and modernization of existing systems.

The role involves end-to-end ownership, from understanding business requirements and technical design to development, testing, release, and ongoing support.

You will work closely with Product, Support, and other engineers, contribute to technical discussions and code reviews, and help maintain a high technical standard across the team.

Responsibilities

• Design, build, and maintain scalable Python backend services and REST APIs.
• Own features end-to-end, from requirements and technical design to testing, release, and support.
• Work with large datasets and identify performance and memory bottlenecks.
• Investigate complex production and customer issues and deliver reliable long-term solutions.
• Improve and modernize existing code while maintaining stability and backward compatibility.
• Translate business requirements into scalable technical solutions and contribute to architectural decisions.
• Participate in code reviews, testing, documentation, and technical knowledge sharing.

Must-have requirements

• 5+ years of backend development experience, including strong production experience with Python.
• Strong hands-on experience with FastAPI, Flask, or similar Python frameworks and building REST APIs.
• Strong experience with pandas and NumPy, including processing and optimizing large datasets.
• Solid experience with MongoDB / NoSQL, including data modeling, indexing, and query optimization.
• Experience working with Parquet / PyArrow or similar columnar data formats.
• Practical experience with AWS, particularly services such as S3 and Lambda, or comparable cloud technologies.
• Strong understanding of Python performance and memory optimization.
• Strong software engineering practices: Git, Docker, CI/CD, automated testing, and code review.
• Experience working with large or evolving codebases, including refactoring and modernizing existing systems.
• Strong ownership mindset, with the ability to take features from requirements through production and support.
• Good English communication skills and ability to work closely with Product, Support, and Engineering teams.

Nice to have

• Advanced AWS experience, including ECS, Infrastructure as Code, AWS CDK / CloudFormation.
• Experience with Redis or DynamoDB.
• Experience integrating AI/ML services into backend applications.
• Experience with Amazon Bedrock, MCP / FastMCP, or similar AI technologies.
• Experience using AI-assisted development tools such as Claude Code.
• Knowledge of time-series forecasting, OLAP, data aggregation/disaggregation, or demand planning.
• Knowledge of CPG/FMCG, supply chain, or commercial planning domains.
• Experience with Cython or other approaches to Python performance optimization.
• Experience with observability tools such as Sentry.
• Frontend knowledge, particularly React / TypeScript, is a plus.
• Experience with architecture documentation and Architecture Decision Records (ADRs).

9 reasons to join us:

1. Today we're working with the technology of tomorrow.
2. We don't wait for a change. We are the change.
3. We're experts in creating experts (Levi9 academy, Lead9 program for leaders).
4. No micromanagement. We are free birds with a clear understanding of what the high performance is!
5. Learning in Levi9 never stops (unlimited Udemy for business, meetups, English courses, Professional trainings).
6. Here you can train your body and mind.
7. We've gathered the best locations - comfortable, cozy and pet-friendly offices in Kyiv (5 minutes from Olimpiyska subway station) and Lviv (5 minutes from the Opera Theatre) with regular offline internal events
8. We have master's degree in work-life balance.
9. We are actively supporting Ukraine with constant donations and volunteering

Simple step to get this job

Click the APPLY NOW button and leave your contacts!