Senior Software Engineer, Billie AI team
Software Engineering, Data Science
Belgrade, Serbia
USD 84k-108k / year
Posted on Oct 23, 2026
Key responsibilities
- Build and improve AI voice and chat agents that handle thousands of patient conversations every day.
- Work on real-time systems where low latency, high concurrency, and reliability are critical.
- Develop AI-powered cost estimation algorithms using LLMs and statistical analysis of historical data.
- Analyze production data, identify patterns, form hypotheses, test hypotheses, improve accuracy.
- Design backend systems that handle high traffic, external integrations, and complex workflows.
- Own features end to end. From understanding the business problem to implementation, production monitoring, and measuring results.
- Build metrics and dashboards to understand how our products perform and where they need improvement.
- Make pragmatic engineering decisions. Know when to move fast and when correctness and reliability cannot be compromised.
- Challenge product ideas, propose better solutions, and defend your decisions with data and business reasoning.
What you'll do
Required qualifications
- Strong Python and PostgreSQL experience.
- Solid system design skills. Ability to make and explain architectural decisions.
- Experience with data analysis, SQL, and building metrics to support decisions.
- Experience using AI coding tools in your daily workflow.
- Strong product and business thinking -- Ability to understand business requirements, evaluate trade-offs, and make decisions based on customer and business impact.
- End-to-end ownership -- Experience taking projects from initial requirements through design, implementation, deployment, and measuring results.
- Experience writing and evaluating prompts for production AI systems.
- Experience building AI-powered products.
What we're looking for
Nice to have
84000 - 108000 USD a year