Product Engineer (Backend) | UK / EU

High-Impact Backend Role | AI-Native Legal Platform Remote (GMT-5 to GMT+1 overlap) UK & EU Only | Optional hubs: London / New York Full-time | Mid–Senior £100,000 – £200,000 + meaningful equity Our client — AI-native LegalTech company Travel: London every 5–6 weeks Work Authorization Must be eligible to work in the UK, EU No visa sponsorship currently specified Must be able to travel to London every 5–6 weeks About the Opportunity Our client is rebuilding legal services from the ground up. Backed by $9M+ from a tier-1 US VC , the team is creating a Cursor-like environment where lawyers collaborate with AI agents on real legal work. You will join a small, high-caliber engineering team growing from 2 to 5 , with direct ownership over systems used daily by real lawyers. This is a product-first backend role where reliability, safety, and extensibility are mission-critical. What You'll Build Core product APIs powering matters, documents, chats, and permissions Scalable data models supporting evolving agent workflows Agent-facing backend primitives enabling safe autonomous actions Production infrastructure focused on reliability and observability Systems that remain auditable, reversible, and correct in real legal workflows Tech Environment Python (core backend language) Postgres (primary datastore) Cloud infrastructure (GCP preferred) API-first product architecture AI-assisted engineering workflows What They're Looking For Strong production experience with Python backend systems Proven API and data model design capability Experience translating product goals into reliable backend architecture Track record of owning systems end-to-end in fast environments Comfortable working remotely with required time zone overlap Nice to Have Experience building products from zero to one or early-stage startup experience Experience with Postgres at scale Exposure to Temporal or background job systems Familiarity with GCP environments Background in collaborative or workflow-heavy SaaS Why This Role Stands Out Meaningful equity in a well-funded early-stage company Unlimited budget for AI coding tools Real product ownership from day one Annual Mallorca offsite + regular team gatherings Tight feedback loop with real legal users Early-stage, real users, real ownership — if you build backend systems that must work flawlessly in production, we'd love to meet you...