Software Engineer

Letly; Greater London; On-site; GBP 70,000 - 120,000; Full time

Job summary

Letly is seeking a backend engineer to own and build the core services behind viewing, tenancy, certificates, rent payments and repairs. You’ll ship reliable, scalable code in a role that grows from junior to staff levels, with real production responsibility from day one.

You’ll work on money movement, reconciliation, event-driven consistency and AI-in-production features, with an emphasis on correctness and secure software practices.

Qualifications

• Experienced backend engineer who has built production systems.

Responsibilities

• Money movement: handle rent, deposits and payouts with idempotent processing and exactness across services.
• Reconciliation & bookings: maintain a penny-accurate ledger with viewings, certs and maintenance scheduling.
• Event-driven consistency: coordinate services via Pub/Sub with sagas and deterministic API calls.
• AI in production: deploy agentic AI with guardrails and observability to manage real-world data.

Job description

The role

You'll build and own the backend systems Letly runs on — the software behind every viewing, tenancy, certificate, rent payment and repair. These are systems where correctness, reliability and scale are non-negotiable: real people's money, homes and legal exposure are on the line.

This is one role hiring at every level, junior to staff — we level on the scope you own, not years served. At junior you ship features inside services others own, with review, mentoring and real production responsibility from the first month — the fastest engineers here ask early and close the loop quickest. At mid you own features and services end-to-end. At senior you own systems others build on — you make the architecture calls, set the patterns, and raise the bar around you. At staff you own the technical direction of a domain: you decide what gets built and how, you unblock other engineers, and you answer for how those systems behave under load.

What you'll work on

• Money movement. Rent, deposits and payouts through pooled client-money accounts — idempotent processing, split-settlement, exactly-once across service and bank boundaries.

• Reconciliation & bookings. A penny-accurate, self-healing ledger reconciling bank activity across thousands of tenancies; contended scheduling — viewings, certs, photography, maintenance against finite slots and vendor availability.

• Event-driven consistency. Services coordinating over Pub/Sub — sagas across offer contract tenancy payment with no distributed transaction to lean on. LLM tool calling, deterministic API calls, and other intra- and inter-service communications all running across the same coordination system.

• AI harnesses in production. Deploying agentic AI into real-world operational settings — acting on real money, tenancies and legal exposure, with the guardrails, observability and correctness that demands. Non-deterministic LLM working within compliant, secure deterministic software.

Our stack

We build on NestJS + TypeScript on GCP / GKE, with MongoDB, Redis and GCP Pub/Sub.

You don't need to arrive fluent in it. We hire strong backend engineers who've built production systems with any robust framework — Java/Spring Boot, Go, Kotlin, C#/.NET, Python (Django/FastAPI) or Ruby on Rails — and can ramp into TypeScript fast. We care that you've built and operated real backends, not which language you did it in.

How we build

Small, well-factored services. TDD and DDD as defaults. Trunk-based CI/CD — you ship to production and own it, with tests, observability and clean rollbacks. Lean frameworks, readable code, and we move fast because the tests and boundaries let us.

What we're looking for