Full Stack Engineer

About Litmas.ai

LITMAS is an AI-powered litigation platform that streamlines litigation workflows, enabling lawyers and legal teams to manage cases more efficiently from intake through resolution. We're seeking a Founding Full Stack Engineer to join our core team and shape the technical foundation of LITMAS. This is an opportunity to build a product from the ground up, working directly with the founders to create technology that supports attorneys in their legal practice. As a founding engineer, you'll have significant ownership over our technical architecture, product decisions, and engineering culture.

This is a full-time, hybrid position for candidates based in London. You are required to be in the UK office 3 days a week.

Key Responsibilities

• Architect and build core platform features using Python, Node.js, Next.js, React, and MongoDB
• Design and implement production-grade LLM systems with advanced tool usage, RAG pipelines, and agent architectures
• Build AI workflows that combine multiple tools for legal research, validation, and document analysis
• Create scalable RAG infrastructure to handle thousands of legal documents with high accuracy
• Implement AI tool chains to provide agents with tool inputs
• Design intuitive interfaces that make complex legal workflows simple and powerful
• Own end-to-end features from conception through deployment and iteration
• Establish engineering best practices for AI systems including evaluation, monitoring, and safety
• Collaborate directly with founders on product strategy and technical roadmap

Required Qualifications

• Deployed production-grade LLM applications with demonstrable experience in:
• Tool usage and function calling
• RAG (Retrieval-Augmented Generation) implementation at scale
• Agent architectures and multi-step reasoning
• Prompt engineering and optimization
• Knowledge of multiple LLM providers (OpenAI, Anthropic, Cohere, open-source models)
• Experience building AI evaluation and monitoring systems
• Experience with document processing and OCR technologies
• 5+ years of production experience with Node.js, Python, Next.js, and React
• Strong MongoDB expertise including schema design and optimization
• Experience with vector databases (Pinecone, Weaviate, Qdrant, or similar)
• Full-stack development capabilities with ability to own features from database to UI
• Track record of shipping complex web applications at scale
• Deep understanding of LLM limitations, hallucination prevention, and validation techniques

What We Offer

• Competitive salary and equity package
• Opportunity to shape the technical direction of a category-defining product
• Direct collaboration with founders on product and company strategy
• Hybrid work environment
• Professional development opportunities

To Apply

Please submit 1) your resume 2) links to relevant projects or GitHub repos and 3) a brief note on the most challenging AI/LLM problem you’ve solved in production. Send your application materials via email to careers@litmas.ai with the subject line "Founding Full Stack Engineer - [Your Name]" or DM us directly on LinkedIn with your application materials.