Senior Python Backend Engineer - AI/ML

About the Role:

We are looking for a hands-on Senior Python Backend Engineer to build and scale an AI-driven sustainability platform. The role combines Python backend engineering, API development, data processing, and applied AI/LLM workflows.

You will work closely with engineering, product, QA, and domain experts to convert complex requirements into reliable, scalable, and production-ready solutions.

Key Responsibilities:

• Design, develop, and maintain scalable FastAPI/Python backend services and REST APIs.

• Build LLM/RAG-based applications, including prompt workflows, structured outputs, retrieval, grounding, and guardrails.

• Develop rule-based validations and workflows with proper traceability and auditability.

• Build reliable Celery-based background jobs with retries, monitoring, and failure recovery.

• Design data models and optimise PostgreSQL/SQL queries, caching, latency, and application performance.

• Write unit and integration tests using pytest and maintain high engineering standards.

• Contribute to Docker, Git, CI/CD, observability, security, and cloud deployments.

• Troubleshoot issues across applications, databases, distributed jobs, and third-party integrations.

• Collaborate with product, QA, engineering, and sustainability/LCA specialists to deliver features in Agile sprints.

Required Skills:

• 5+ years of professional software development experience with strong hands-on Python backend expertise.

• Strong production experience with FastAPI, Python, Pydantic, asynchronous programming, and service architecture.

• Good knowledge of REST APIs, authentication, validation, error handling, and API versioning.

• Strong experience with PostgreSQL/relational databases and SQLAlchemy or similar ORM.

• Hands-on experience with Celery and Redis/RabbitMQ or similar messaging systems.

• Experience developing LLM applications, RAG, embeddings, semantic search, structured outputs, or vector databases.

• Experience with pytest, Docker, Git, code reviews, CI/CD, and cloud-based applications.

• Strong debugging, analytical, and problem-solving skills.

• Good communication and ability to work with both technical and non-technical stakeholders.

• Interest in sustainability, climate technology, ESG, LCA, or carbon accounting is preferred.

Good to Have:

• Experience with LangChain, LlamaIndex, or similar LLM frameworks.