Founding Backend Engineer - AI/ML & Knowledge Retrieval (London Area)

Location: Hybrid – London (Euston) · 2–3 days per week in‑office

Employment Type: Full‑time

Praktiki’s cross‑platform app delivers vetted, evidence‑based answers to frontline clinicians in seconds. We combine large‑language models with rigorous retrieval‑augmented generation (RAG) pipelines so doctors can safely consult clinical guidelines at the bedside. You’ll join a small, product‑obsessed team that ships fast and is mission driven.

As our Founding Backend Engineer , you will steer the technical direction, culture, and architecture of our AI‑powered knowledge platform. You’ll own the services that ingest, index, and serve medical content for our Q&A feature. You’ll design scalable APIs, optimise vector search, evaluate ranking quality, and productionise LLM workflows on Google Cloud.

• Design & build backend micro‑services (Python/FastAPI) that power RAG pipelines, user queries, and analytics.
• Develop retrieval infrastructure : orchestrate embedding generation, vector databases (PGVector, Pinecone, Weaviate), and hybrid search.
• Implement evaluation framework for search quality and answer accuracy (BLEU/ROUGE, human‑in‑the‑loop, automatic hallucination checks).
• Deploy & monitor services on GCP (Cloud Run, Vertex AI, Pub/Sub, BigQuery) with Terraform, CI/CD, logging, metrics, and alerting.
• Collaborate closely with product, mobile, and medical SME teams to refine requirements and ship weekly increments.
• Champion best practices in testing, secure data handling (NHS DSPT), and GDPR compliance.

Python • FastAPI • LangChain/LlamaIndex • PostgreSQL + PGVector • Redis • Pinecone/Weaviate • Vertex AI • Cloud Run • Docker • Terraform • Prometheus/Grafana • GitHub Actions

• Master’s degree in Computer Science, Software Engineering, or related field; or equivalent practical experience.
• 5+ years building production backend systems (Python preferred).
• Proven track record shipping ML, search, or recommender systems at scale.
• Deep understanding of vector similarity search, embeddings, and LLM‑powered RAG.
• Hands‑on experience with GCP (or AWS/Azure) and infrastructure‑as‑code.
• Strong grasp of testing, observability, and performance optimization.
• Excellent communication; comfortable working in a fast‑moving, product‑led startup.
• Thrives in an early‑stage environment, embraces ambiguity, and brings a growth‑mindset to scale both product and team.
• Able to work in‑office in Euston 2–3 days per week (right to work in the UK required).

• Clinical or health‑tech domain knowledge.
• MLOps tooling (MLflow, Kubeflow, Vertex Pipelines).

• Competitive salary and attractive equity in a high growth startup
• 25 days holiday + UK bank holidays.
• Flexible hours & focus on sustainable pace.
• Bright office minutes from Euston.

Praktiki is an equal‑opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. If you’re passionate about building tools that help clinicians make better decisions, we’d love to hear from you.