Senior ML Back-end Engineer

The Role We are looking for a Senior Engineer to architect the backbone of our financial decisioning platform. You will not just build APIs; you will design the high-concurrency systems that serve our ML models in real-time. You will set the standards for Asynchronous Python, Database Performance, and System Observability, while mentoring junior engineers to write robust, production-grade code.

Key Responsibilities

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• System Architecture: Design and maintain high-performance, asynchronous microservices using FastAPI. Make critical architectural decisions regarding API standards (REST vs GraphQL) and service boundaries.
• ML Integration: Integrate machine learning models into core backend services and business workflows. You will orchestrate how our applications consume internal model APIs (e.g., Credit Scoring, Pricing) to ensure seamless decision-making.
• Database & Data Modeling: Own the schema design in PostgreSQL. Optimize complex queries, manage migrations using Alembic, and ensure strict data validation standards using Pydantic.
• Observability Strategy: Define and implement the logging, tracing, and metrics strategy using OpenTelemetry and the Grafana Stack (Loki, Tempo, Prometheus). Ensure we have full visibility into system latency and health.
• Engineering Excellence: Enforce high code quality standards through code reviews. Champion Functional Programming patterns, rigorous testing (PyTest), and Clean Architecture principles.
• Mentorship: Act as a technical lead for the squad, guiding junior engineers in debugging, design patterns, and git workflows.
• Experience: 5+ years in Backend Engineering, with significant exposure to data-intensive applications or Fintech.
• Python Mastery: Expert-level knowledge of Python 3.10+. Deep understanding of AsyncIO, concurrency, and Functional Programming paradigms.
• Framework Expertise: Proven experience scaling FastAPI applications in production. Knowledge of dependency injection, middleware, and ASGI standards.
• Database Internals: Advanced knowledge of PostgreSQL (indexing, locking strategies, query planning) and experience with ORMs/Migration tools (SQLAlchemy/Alembic).
• Infrastructure & DevOps: Strong experience with Docker, CI/CD pipelines, and modern package managers (e.g., uv, Poetry).
• Code Quality: Strong ability to write highly optimized, clean, and maintainable code. You understand algorithmic complexity, memory management, and how to write Python that performs efficiently at scale.
• GenAI (Bonus): Knowledge of GenAI application development (LLMs, RAG, Vector Databases) is a strong plus.

• Office environment: When you come to our b_labs office, you'll find creative workspaces and an open design to foster collaboration between teams.
• Flexibility: You know best whether you want to work from home or in the office.
• Equipment: From "Day 1" you will receive all the equipment you need be successful at work.