Founding Engineer (Full Stack) – AI Platform for Litigation w/ 0.25%–1.0% Equity

Bounty Amount: $8,025 - 12,000

Company Name: Crimson

Role Type: Full-Time

Location: London, UK (3+ days/week in-office near Bank)

Salary / Hourly Rate: $107,000 - $160,000 per year

Benefits: Needs to work in the UK.,US citizenship/visa not required (from YC card).,Open to candidates willing to relocate to London, but prefer people already UK-based / London-based (you can reflect this in notes).

Role Information

Role Overview: N/A

Responsibilities: This is a founding full-stack engineering role. You’ll join Crimson as one of the first employees and help build the AI platform that powers litigation at leading UK and US law firms.What you’ll do:• Contribute across the entire stack, from cloud infrastructure to prompting to UX – including Python backend, Next.js + TypeScript frontend, PostgreSQL, and Azure-hosted LLM workloads with CI/CD pipelines (GitHub Actions, IaC such as Bicep).• Collaborate closely 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, summarisation and data extraction over large volumes of legal documents.• Design and implement intelligent, multi-step agent workflows that can autonomously handle complex legal tasks – from surfacing key testimony to generating fact chronologies and spotting inconsistencies in filings.• Design and bring to life intuitive, AI-native user experiences tailored to litigation workflows, in partnership with the founders and early customers.• Improve system performance, stability and observability as we scale to more cases, larger datasets and additional firms.• Help shape our engineering culture and team – from best practices and code standards to interviewing, hiring and mentoring future engineers.

Qualifications: 3+ years of experience 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 (Azure preferred; AWS or GCP also relevant)., Frontend experience with modern TypeScript frameworks (Next.js / 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 / documents., Comfort working with LLMs and applied AI – prompting, integrating model APIs, and thinking carefully about correctness, reliability and UX for AI-powered features., Excellent product judgement, communication skills and attention to detail – you’re comfortable talking to demanding users and turning their feedback into shipped features., High agency and bias for shipping; you like 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.

Minimum Requirements: 3+ years of professional software engineering experience, building and shipping production web applications (full-stack).,Strong experience with Python and PostgreSQL on the backend, and TypeScript/Next.js (or similar React framework) on the frontend.,Track record of owning features end-to-end in a small, high-ownership or startup environment, including talking directly to users.,Based in (or willing to relocate to) London, with existing right to work in the UK and ability to be in the office at least 3 days per week.

Screening Questions: (Optional Video). This step is completely optional. If you’d like, record a short 2–3 minute video introducing yourself and your experience — or share a recording of your interview with the recruiter if that’s easier. You can upload the link via Loom or Google Drive. This just helps us get to know you better, but there’s no pressure if you’d prefer to skip it.,(Optional Portfolio / GitHub) If available, please share a link to your GitHub, portfolio, or any recent projects you’ve worked on. This is entirely optional but helps provide more context about your work.,Have you worked closely with demanding professional users (e.g. lawyers, finance, or similar) and built full-stack features end-to-end for them? Please share an example of a product or feature you owned, including how you gathered requirements and iterated after launch.

Company Information

About Company: N/A

Culture: N/A

Additional Information

Interview Process: Intro Call (30 min) – Introductory conversation with one of the founders to learn more about your background, walk through Crimson’s product and users, and assess mutual fit., Technical Deep Dive (60–75 min) – Live discussion with a founder covering your experience building and shipping full-stack products, system-design style questions, and how you’ve handled complex, real-world requirements., Practical Exercise / Case Study (60–90 min) – Short take-home or live exercise focused on how you’d design and implement a Crimson-style feature (for example, a document ingestion + search workflow or an AI-assisted litigation task), followed by a review with the team., Founder Round (60–90 min) – Conversations with the founding team to go deeper on collaboration style, product thinking, and mission alignment, plus any remaining technical topics.

Day to day: Contributing across the stack – from Python backend and document pipelines to Next.js + TypeScript frontend, PostgreSQL, and Azure-hosted LLM workloads (with IaC + CI/CD)., Collaborating directly with litigators and knowledge workers to understand how they run disputes today, where the bottlenecks are, and how Crimson can slot into their workflows., Designing and scaling ingestion, search and summarisation pipelines over large volumes of pleadings, transcripts, evidence, and orders., Building intelligent, multi-step agent workflows that automate complex legal tasks, while keeping humans in the loop for high-stakes decisions., Iterating rapidly based on user feedback – instrumenting features, debugging real cases, and improving reliability and performance as more firms and matters come onto the platform.

Team: Crimson was founded by Amine Amor (ML/AI specialist), David Strömbäck (AI engineer), and Mark Feldner (former BigLaw litigator)., You’ll work day-to-day with the technical founders on architecture, roadmap, and implementation, and partner closely with Mark to understand how litigators actually use the product in high-stakes cases., The team is small, high-ownership, and product-driven – everyone ships code, talks to users, and has a strong voice in what gets built next.

Growth: Own major parts of Crimson’s architecture and product from day one and shape how the core litigation platform evolves over the coming years., Help define engineering culture from scratch – everything from code standards and observability to how we run interviews and onboard future engineers., Build deep relationships with elite UK and US law firms and see your work used on complex, cross-border disputes that matter., Grow into a tech lead / founding-team engineering leader as the company scales – with meaningful equity in a YC-backed, category-defining legal AI company.

Ideal Candidate Profile: Driven and self-directed – you take ownership of hard problems, operate with high agency, and care deeply about getting to a great outcome for demanding users., Product-obsessed full-stack builder – you’re as comfortable in Python/Postgres as you are in TypeScript/React, and you enjoy sweating the UX details that make AI feel reliable and usable., User-centric communicator – you like talking to lawyers, partners and associates, translating messy workflows into clean technical systems, and iterating quickly based on feedback., Excited by AI in high-stakes domains – you want to push the limits of LLMs in production while caring deeply about accuracy, security and reliability for billion-pound disputes., Bonus: prior experience in legal tech, fintech, or other professional-services products where users are smart, time-poor, and extremely quality-sensitive.

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