Senior Software Engineer

Letly Ltd.; Greater London; On-site; GBP 70,000 - 140,000; Full time

Benefits offered by this job

Private health insurance

Paid gym membership

Three meals a day, in office

Ubers home on late nights

Job summary

Letly Ltd. in London seeks a senior backend engineer to own production systems that handle money and assets, built on a NestJS/TypeScript stack with Python AI services.

You will design service boundaries, ensure safe live migrations, and ship features with emphasis on reliability, observability, and rapid iteration.

Join a small, engineering‑driven team that values clear boundaries, trunk‑based CI/CD, and hands‑on ownership from day one.

Qualifications

• First Class or high 2:1 in Computer Science or equivalent.
• Experience building production backend systems with real users.
• Proficient in at least one backend language/framework and capable of ramping into new stacks.

Responsibilities

• Own production backend systems that handle money and assets.
• Define service boundaries and design trade-offs for live systems.
• Ship features with a focus on reliability, observability, and scale.
• Collaborate closely with AI and infra teams.

Skills

NestJS/TypeScript

Go

System design

Concurrency

HTTP/API design

Testing practices

AI integration

Education

Bachelor's degree in Computer Science or equivalent

Tools

Kubernetes

ArgoCD

GKE / Google Cloud

MongoDB

Redis

Pub/Sub

Nx monorepo

Job description

About Letly

About LetlyLetly is the AI‑Native operating company built for the home. We believe the home should be autonomously run and we're building the software that will run all rental properties end‑to‑end.

The backend at the company is technically difficult on purpose as the operational realities of handling property and money are messy. But the foundations are already there: 10+ backend and AI services, a monorepo on the frontend, GitOps and Kubernetes on the infra side. You'd be building on solid ground rather than firefighting a fragile prototype — with a lot still to build.

We've raised a $4m pre‑seed and are a small, high‑agency, engineering‑oriented team, growing revenue at >100% month‑over‑month. We're hiring to facilitate this aggressive growth.

Our stack

Backend — a microservice architecture in NestJS and TypeScript, with Python and FastAPI for the AI agent services.

• Data — MongoDB Atlas and Redis.

• Event‑driven — services coordinate over Pub/Sub rather than calling each other directly.

• Infra — Kubernetes on GCP (GKE), deployed via ArgoCD.

• Frontend — Angular in an Nx monorepo.

How we build small, well‑factored services with clear boundaries. Tests are written alongside the code, not after it — they're what lets us move quickly without breaking things that handle money. Trunk‑based CI/CD: you ship to production and own it, with observability and clean rollbacks. Lean frameworks, readable code.

We work on a wide spectrum of technical challenges from money movement to operational logistics (scheduling, bookings, access) mediated over event‑driven systems, to building around AI agents in production that are capable of executing autonomously under the hood.

What we're looking for

You've built and operated production backend systems that real users depended on. We care about the scope you've owned and how you owned it.

• First Class or high 2:1 (or international equivalent) in Computer Science or a relevant technical field.

• Fluency in at least one backend language and framework. You don't need to arrive fluent in our stack: we hire engineers who've built production systems with any robust framework — NestJS/TypeScript, Java/Spring Boot, Go, Kotlin, C#/.NET or Ruby on Rails — and can ramp into TypeScript fast.

• System design: where a service boundary belongs, what a design trades away, how services coordinate — events, queues, retries that are safe to repeat — and how it holds up once it's live.

• Fundamentals: concurrency, HTTP and API design, auth, data modelling and transactions (document or relational), changing a live schema safely, and what happens when a call fails.

• Tests: you treat tests as part of shipping, you work comfortably in a shared trunk, and you can quickly understand a large codebase you didn't write.

• You use AI heavily and still know exactly what you shipped. Generated code has the same quality bar as what you wrote by hand: you can explain every line, you've thought about the constraints it has to bear, and you don't merge anything you couldn't have written yourself.

How you work

Hyper‑focus on detail. These systems move money and manage assets; we have low tolerance for "mostly right".

• First‑principles reasoning. You take a hard problem apart rather than reaching for the nearest familiar pattern.

• Communication clarity. You can explain a complex trade‑off to another engineer, and to someone who doesn't write software — because here you'll have to do both.

• Ownership mentality. You own the outcome, not the ticket: start to production, without being chased.

• Collaborative. Teams change the world, not individuals. You make the next engineer better and faster.

• Adaptability. You do well in a fast‑moving environment where requirements shift under you.

• Learning velocity. You pick up new paradigms quickly and don't need long to get productive in unfamiliar territory.

• Quality‑obsessed. Not just the code — the tests, the docs, the handover, the thing you leave behind.

Our process

We aim to complete end‑to‑end in under a week.

• Screening — 30 minutes with the CEO

• Skills — 45 minutes with the CEO & CTO

• Problem solving — 60 minutes with the CTO

• Slope — 45 minutes with the CEO

• Offer — references and a decision in days

Benefits

On top of base salary, equity and annual bonus, you're also entitled to:

• Private health insurance

• Paid gym membership

• Three meals a day, in office

• Ubers home on late nights

Compensation

Compensation: £70K – £140K Multiple Ranges

• Mid £70K – £100K

• Senior £90K – £140K