Full Stack AI Engineer

With a legacy as a pioneer in the ALSP market, Factor leads the next evolution in legal services through AI-integrated contracting.

Factor is the market leader in Integrated Law, combining the expertise of Traditional Law, the efficiency of New Law, and the close business integration of In-house legal to deliver complex legal work at scale.

Factor works alongside corporate legal departments to solve for the ever-increasing demands and complexity of transactional legal work. Our "do while transforming, transform while doing" approach combines specialist expertise, AI-powered solutions, and business process knowledge to deliver better performance, better business and legal outcomes, and a transformed contracting experience.

Our clients span Fortune 500 companies including global banks, major pharmaceutical companies and large technology firms.

We believe that the more diverse our team becomes - in backgrounds, skills, experiences, and perspectives - the higher our creative potential as a company. We are dedicated to growing a diverse, inclusive company where individuals of all backgrounds thrive.

We are comprisedof more than 300 lawyers, legal specialists, technologists, and process consultants across Europe and North America - Join us!

Factor Law is hiring a Full Stack AI Engineer to build production-grade AI products for complex legal workflows. This is a hands-on engineering role for someone who can move confidently from backend architecture to frontend delivery, from document ingestion to user experience, and from prototype to production without waiting for detailed step-by-step instructions.

You will join a high-autonomy product and engineering environment building AI-powered tools that help legal teams work faster, more accurately and with more confidence. The work will sit at the intersection of contract intelligence, document processing, retrieval, AI orchestration, workflow automation, enterprise authentication, asynchronous job handling and complex user interfaces.

This role is for a builder. We are looking for someone who can use AI-assisted coding tools aggressively and responsibly, particularly Codex, while still owning correctness, security, maintainability and production quality. The right person will use AI to move faster, not to cut corners.

• Build production services using Python, FastAPI and Pydantic models.
• Develop APIs and backend workflows that support AI-enabled document and contract intelligence.
• Work with Postgre
  
  SQL, SQL Alchemy and Alembic to model, migrate and operate reliable data layers.
• Build and maintain asynchronous job systems, including queue processing, retries, idempotency, dead-letter handling, cancellation, progress tracking and failure recovery.
• Use Redis for caching, transient state, job status and coordination, with sensible reliability patterns such as timeouts, circuitbreakers and graceful degradation.
• Build React and Type Script interfaces that consume backend services cleanly and provide users with transparent job states, useful error handling and polished interaction patterns.
• Use Tan Stack Query for server state, including query key factories, cache invalidation, optimistic updates and polling patterns for long-running AI jobs.
• Support document-heavy workflows, including ingestion, retrieval, structured extraction, redlining, rich text editing and AI-assisted review.
• Build features that respect enterprise security expectations, including authentication, authorization, secure data handling and auditability.
• Operate within Azure-based environments, including services such as Blob Storage, Key Vault, managed databases, Redis and containerised deployments.
• Instrument production systems using Application Insights or equivalent observability tooling.
• Use AI coding tools to accelerate implementation, debugging, refactoring, testing and documentation, while maintaining high code quality.
• Improve developer experience by reducing boilerplate, improving test coverage, simplifying local setup and documenting repeatable patterns.
• Move fluidly between infrastructure and product delivery when needed.

• 3-5 years of professional software…