Senior Software Engineer

About the team

We are a startup-like, full-stack team building production software systems, AI-powered applications, and backend platforms inside one of the leading banks in Bulgaria.

Our work ships to real customers. If you use the mobile app or website, you’re likely interacting with systems we built, such as:

an AI assistant (with upcoming capabilities to analyze real-time transactions and provide personalized financial guidance)

real-time product ranking that adapts instantly to your explicit feedback

AI-powered search engine for the website

and other software, ML/AI products and backend platforms across the bank

We are growing and looking for a self-driven, results-oriented Senior Software Engineer who enjoys solving complex backend and system-design challenges and building production-grade software with large-scale impact.

We value strong software engineering fundamentals over experience with any particular framework. We believe frameworks and technologies can be learned, while good engineering judgment, problem-solving ability, clean code, and strong fundamentals are much harder to develop.

As part of our team, you will

• Design, develop, and maintain high-performance backend services and APIs using Python and FastAPI.
• Take end-to-end responsibility for software components: requirements, architecture, implementation, testing, deployment, monitoring, and ongoing improvements.
• Design and implement scalable APIs and distributed services capable of handling production workloads.
• Work with both SQL and NoSQL databases, selecting the appropriate technology and data model for each use case.
• Design efficient database schemas, queries, indexes, and data access layers, with a strong focus on performance and scalability.
• Contribute to system architecture and technical decisions, including service boundaries, APIs, caching, asynchronous processing, and reliability.
• Write clean, maintainable, testable, and production-ready code following modern Python best practices.
• Review code, provide technical guidance to other engineers, and contribute to improving engineering standards across the team.

We’re looking for candidates with:

• 5+ years of hands-on experience in software engineering, with strong experience in Python backend development.
• Advanced knowledge of Python, including object-oriented and functional programming, asynchronous programming, concurrency, typing, error handling, and Python ecosystem best practices.
• Strong practical experience with FastAPI or similar modern Python web frameworks.
• Solid understanding of REST APIs, HTTP, authentication/authorization, API design, validation, serialization, versioning, and error handling.
• Strong knowledge of SQL and relational databases, especially PostgreSQL, including complex queries.
• Good understanding of NoSQL databases and when to use them, including technologies such as Redis, MongoDB, Elasticsearch/OpenSearch, or similar.
• Strong understanding of data structures and algorithms, with the ability to analyze time and space complexity and choose appropriate solutions for real-world problems.
• Excellent understanding of software design principles and patterns, abstraction, and modular architecture.
• Proficiency in writing clean, efficient, readable, and maintainable code, with a strong focus on code quality and long-term maintainability.
• Experience writing unit, integration, and API tests, including effective use of mocking and test isolation.
• Good understanding of Git, CI/CD, Docker, and containerized applications.
• Experience working with Linux and cloud environments, preferably Azure.
• Verbal and written English at Upper-Intermediate level or above.

While not required, the following will make you stand out:

• Experience with distributed systems, microservices, Kubernetes, Helm, and cloud platforms such as Azure.
• Experience with Kafka, Redis, SQLAlchemy, and asynchronous/event-driven architectures.
• Experience with NoSQL databases such as MongoDB or Elasticsearch/OpenSearch.
• Knowledge of observability, monitoring, performance optimization, concurrency, and high-throughput systems.
• Frontend experience with React/TypeScript or willingness to contribute to frontend development when needed.
• Experience integrating AI/ML or LLM-powered applications into production systems.

What we offer to you

• EU Blue Card + low taxes and the lowest cost of living in the EU.
• Cutting-edge tech stack on par with top global IT companies.
• Dev-to-Prod in a few clicks via our in-house ML & AI platforms.
• Salary: 3K+ EUR NET + an annual bonus of up to 2 salaries.