TrafficStars is an ad network processing over 10+ billion ad impressions daily, operating on 500+ servers across data centers in Europe and the US, and handling more than 1 million requests per second during peak hours.  Our ClickHouse cluster stores 3.6 petabytes of data. At this scale, the platform remains stable and predictable thanks to a well-designed architecture and a strong engineering team.

Who we are looking for:

We are looking for a Senior Python Developer to join our API vertical. This vertical is responsible for corporate APIs, integrations with external services, and advertising pricing management systems. The team is product-oriented and works in SCRUM alongside high-load Go developers and frontend engineers.

What makes this role senior:

• Business domain: AdTech involves auctions, targeting, billing, anti-fraud systems, and internally developed products with years of accumulated business logic. Technical decisions are heavily dependent on understanding how the business works.
• Scale: 10+ billion impressions per day, 1M+ RPS at peak, and a 3.6 PB ClickHouse cluster. We expect scalability and performance concerns to be addressed at the design stage, not after deployment.
• Existing services : A significant part of the work is maintaining and evolving systems that have been running in production for years. You should be equally comfortable building from scratch and working with legacy code.

Our expectations:

• Deep understanding of Python internals: execution model, asynchronous programming (AsyncIO), typing, profiling, and performance optimization under high load;
• Strong FastAPI expertise at the service architecture level;
• Experience developing high-load services (10k+ RPS);
• Production experience with PostgreSQL and/or ClickHouse: query optimization, execution plan analysis, handling large datasets;
• Strong SQL skills are mandatory;
• Experience with message brokers (Kafka, RabbitMQ, or similar): delivery guarantees, idempotency, processing patterns;
• Systematic approach to testing: unit, integration, and load testing;
• Understanding of design patterns and the ability to apply them appropriately without overengineering.

Nice to have:

• Confident Linux usage and networking knowledge sufficient for troubleshooting production incidents;
• Ability to read and understand Go code;
• Experience in AdTech, FinTech, or other domains with high business complexity.

Responsibilities:

• Design and develop services in Python;
• Evolve the architecture of existing services to support increasing load;
• Performance optimization: profiling, identifying, and eliminating bottlenecks;
• Design and maintain integrations with external systems;
• Participate in architectural decisions within the vertical;
• Decompose and estimate complex tasks with domain context in mind;
• Conduct code reviews and maintain code quality standards;
• Investigate incidents and consult second-line support on possible solutions for users.

We offer:

• All-white salary above the market average;
• Lack of dress code and bureaucracy;
• A work laptop of your choice: Mac or PC;
• Tickets to Cyprus covered by the company;
• Work visa for the employee and visitor visas for family members;
• Housing provided for the first month;
• Medical insurance and mobile communications;
• Support with family relocation from any region;
• Free lunches and drinks;
• Fresh fruits and snacks always available in the office;
• Free English courses;
• Compensation for sports activities;
• Partial coverage of school and kindergarten fees.

Join our team!