Founding Engineer (Full Stack) – w / Equity

TEN-XER; City Of London; On-site; GBP 60,000 - 80,000; Full time

Job summary

A tech company specializing in legal tech is seeking a full-stack engineer to build AI-driven tools that change how legal disputes are resolved. This role entails developing core product features, working directly with users, and designing intelligent workflows. Candidates should have over 3 years of experience in production web applications, strong Python skills, and a knack for frontend development with TypeScript frameworks. The position offers equity, the opportunity to work closely with founders, and the chance to significantly influence the efficiency of litigation teams.

Benefits

Equity

Direct access to founders

Impactful work on critical legal disputes

Qualifications

• 3+ years building and shipping production applications in a startup environment.
• Strong backend experience with Python and cloud infrastructure like Azure.
• Frontend skills with modern frameworks such as Next.js or React.

Responsibilities

• Build core product features across the stack, including cloud infrastructure.
• Work directly with litigators to understand their workflows.
• Design and implement workflows for complex legal tasks.

Skills

Production web applications full-stack

Python

PostgreSQL

Azure

TypeScript frameworks

Data pipelines

LLMs and applied AI

Excellent product judgment

Communication skills

Attention to detail

Job description

About Ten-Xer

At Ten-Xer, we match people to roles where they can actually build and grow. We partner with startups that want operators, not passengers, and help them hire talent who move fast and deliver outcomes.

About Crimson

Crimson is an AI productivity platform built for litigators. Litigation teams use Crimson to analyze case files, answer case-specific questions and draft documents tailored to each dispute. By automating manual workflows across the life cycle of a case, Crimson helps lawyers find key evidence faster, streamline case management and save 10+ hours per week on common litigation tasks.

Crimson is a small, high-ownership team of three co-founders building a category-defining AI platform for high‑stakes litigation. They work with major UK and US law firms on highly sensitive case files. The culture is product-driven and security‑obsessed: engineers talk directly to users, own features end‑to‑end, and care deeply about accuracy, reliability and speed. YC‑backed and focused on shipping quickly while learning from demanding users.

What You’ll Do

• Build core product features across the stack from cloud infrastructure to prompting to UX, including Python backend, Next.js with TypeScript frontend, PostgreSQL, and Azure‑hosted LLM workloads with CI / CD pipelines via GitHub Actions and IaC such as Bicep
• Work directly with litigators and knowledge workers to understand how lawyers work, what they need, and how Crimson can fit into their workflows
• Architect and scale document ingestion and processing pipelines to power fast, accurate search, summarization and data extraction over large volumes of legal documents
• Design and implement intelligent, multi‑step agent workflows that autonomously handle complex legal tasks from surfacing key testimony to generating fact chronologies and spotting inconsistencies in filings
• Design and ship intuitive, AI‑native user experiences tailored to litigation workflows in partnership with founders and early customers
• Improve system performance, stability and observability as the platform scales to more cases, larger datasets and additional firms
• Shape engineering culture and team standards from best practices and code quality to interviewing, hiring, and mentoring future engineers

What You Bring

• 3+ years building and shipping production web applications full‑stack, ideally in startups or small, high‑ownership teams
• Strong backend experience with Python or similar, PostgreSQL, and cloud infrastructure with Azure preferred but AWS or GCP also relevant
• Frontend experience with modern TypeScript frameworks like Next.js or React, and an eye for building clean, intuitive product experiences
• Experience designing and operating data pipelines or distributed systems that handle large volumes of text or documents
• Comfort working with LLMs and applied AI including prompting, integrating model APIs, and thinking carefully about correctness, reliability and UX for AI‑powered features
• Excellent product judgment, communication skills and attention to detail with comfort talking to demanding users and turning their feedback into shipped features
• High agency and bias for shipping with a preference for owning problems end‑to‑end and seeing your work used in real cases
• Bonus: interest or background in legal tech, disputes, or working with professional services users

Why this role matters

You’ll be building tools that change how some of the most critical legal disputes get resolved. Your work will directly impact case outcomes, billable efficiency and how litigation teams operate under pressure. You’ll have equity, direct access to founders and users, and the chance to define what AI tooling for law should actually look like.