Full-Stack Engineer

About the role

The basics

Β£75K-Β£110K base + meaningful equity

Hoxton, London. In-office 5 days a week, on-site.

PLEASE DO NOT APPLY IF YOU ARE NOT IN THE UK

This will be the hardest job you've ever had.

We operate with the intensity and speed of an SF YC-stage startup, but in London. Shipped features, not endless planning. We need an engineer who can own technical systems end-to-end and thrive in a fast-paced, high-stakes, five/six-day-a-week environment.

πŸ‘‹ What we're building

Our starting point is selling to real estate agencies, where we're replacing manual workflows with AI employees that handle tenant engagement, landlord outreach, compliance, and maintenance autonomously.

Property is one of the most important parts of people's lives, and the experience of buying, selling or renting one is still terrible. The industry is fragmented, compliance-heavy, and deeply inefficient. It runs on spreadsheets, missed calls, and manual processes that haven't changed in 30 years.

Nobody has built the definitive AI agent layer for real estate yet. That's what we're doing.

πŸ—οΈ About us

  • Backed by Entrepreneurs First and top-tier VCs
  • Live with agencies across the UK with early US traction
  • Building AI agents that don't just assist. They do the work.
  • Based in Hoxton, London. In-office 5/6 days a week.

The Role

As a Full-Stack Engineer, you'll:

Own backend, frontend, infrastructure, and deployment. Full-stack ownership.

  • Make architectural decisions that shape our product
  • Ship features from concept to production in days, not weeks/months
  • Work closely with the founding team on strategic technical direction
  • Mentor future engineers as we scale (you'll be early enough to shape culture)
  • Debug production issues at 2am without hesitation, then ship the fix by morning

You'll touch every layer of what makes our AI agents actually useful in production:

  • The Python / FastAPI backend that orchestrates our agents
  • LLM orchestration and RAG pipelines
  • Telephony and voice infrastructure (real-time calls, STT/TTS)
  • Messaging integrations (WhatsApp, SMS, email)
  • API integrations with property management and CRM systems
  • A Next.js / TypeScript frontend that operators and customers actually use

Required Skills

Mandatory (non-negotiable)

  • Python. Backend systems, scripting, data processing.
  • FastAPI. Async APIs and event-driven services.
  • TypeScript / JavaScript. Modern frontend development.
  • Next.js / React. Production apps real users touch.
  • PostgreSQL + Redis. Data modelling, query design, async patterns.
  • GCP/AWS. Production infrastructure, deployments, observability.

This is not a feature-builder role. You're creating entire systems, making tradeoffs, and owning their outcome end-to-end.

Highly desired

  • Track record building products from 0 to 1 or scaling at an early-stage startup
  • Portfolio demonstrating end-to-end project ownership
  • Hands-on with LLMs in production (orchestration frameworks, vector databases, evals)
  • System design and architecture experience
  • Ability to read unfamiliar code and understand it quickly
  • DevOps / CI-CD pipeline experience

Nice to have

  • 1+ years at a top-tier tech company
  • Previous founding engineer experience
  • Desire to found in the future

We value taste, speed, and a maker's mindset over credentials.

πŸ”₯ How we work

This is not a 9-to-5 role. We operate with YC startup culture in London.

  • 12-hour days are standard. 10am to 10pm or similar flexibility.
  • Five-Six-day working weeks
  • 5 days - In-office in Hoxton
  • High-intensity environment. Fast decisions, high stakes, rapid iteration.
  • Fast feedback loops. Ideas to code to production in days.
  • High ownership, high autonomy. You make calls, not committees.

We're rebuilding a $1T+ industry and we don't think that happens on a 9-to-5.

If you're optimising for work-life balance, predictable hours, or a slow pace, this isn't for you. We need people energised by intensity, not drained by it.

🚫 This role isn't for you if

  • You want a predictable 9-to-5
  • You optimise for work-life balance over output
  • Six days a week in the office sounds exhausting rather than energising
  • You want to feature-build instead of system-build

🎁 What we offer

  • Β£75K-Β£110K base depending on experience, plus meaningful equity
  • Front-row seat to building the AI agent layer for a $1T+ industry
  • A team obsessed with winning. Small, fast, building something that matters.
  • πŸ₯ Private health insurance
  • πŸš— Uber home when you're working late
  • 🍲 DoorDash dinners in the office
  • 🧽 Monthly home clean
  • πŸ’» Brand new MacBook

But the real offer is ownership. You own the system. You make the calls. No committees, no waiting for permission.

πŸ“Œ Hiring Process

Stage 1: Quick chat with our Founder’s Associate

Stage 2: Technical Chat (30 min)

Stage 3: 2-Day In-Person Work Trial

Stage 4: Offer

  • Fast decision (within 48 hours if Stage 3 goes well)
  • Top talent moves quickly. We won't waste your time.

Job Details

Company
Letty
Location
City of London, London, United Kingdom
Posted