Software Engineer (Backend) (up to £200k)

Dex; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

Dex is building an AI operating system for enterprise IT, partnering with teams to place engineers in impactful roles and provide context about the opportunity.

This backend role focuses on owning core platform components, including large-scale batch processing, the LLM gateway, and enterprise-grade auth/observability. The position requires in-person collaboration with the London team, five days a week.

Qualifications

• 3+ years of backend engineering experience with ownership over platform components.
• Experience designing distributed systems with queueing and batch processing.
• Familiarity with LLM infrastructure at scale, including token routing and failover.
• Proven track record building internal tooling or APIs to improve velocity.
• Ability to work in person with the team in London five days a week.

Responsibilities

• Design and build core backend platform components to enable rapid shipping.
• Develop and scale batch job infrastructure handling large data volumes.
• Engineer the LLM gateway with token throughput management and provider failover.
• Establish robust auth and observability defaults for enterprise reliability.
• Build internal tooling and APIs to accelerate product development and team efficiency.

Skills

Backend engineering

Distributed systems

LLM infra

Internal tooling

On-site London

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

Dex is an AI recruiter agent that helps you run your job search. Tell Dex your stack, seniority, and what you want to build. We will manage your applications and surface other opportunities that are a fit.

This company is building an AI operating system for enterprise IT, tackling the complex problem of automating critical, complex workflows for large enterprises. They hire only engineers who can own problems end-to-end, fostering a deliberately talent-dense team where you'll learn from peers and be trusted with significant ownership from day one.

You'll join a lean backend team, owning critical platform components: large-scale batch job infrastructure, the LLM gateway for token throughput and provider failover, and the auth/observability defaults for enterprise reliability. This isn't a role for just implementing features; it's for an engineer who thrives on solving hard, foundational problems across tens of millions of lines of customer code, real-time LLM workloads, and multi-tenant security.

The work

• Design and build core backend platform components, enabling the rest of engineering to ship rapidly.
• Develop and scale batch job infrastructure handling massive data volumes and complex processing.
• Engineer the LLM gateway, managing token throughput, provider failover, and quota across diverse models and providers.
• Establish robust auth and observability defaults, meeting stringent enterprise reliability and security standards.
• Build internal tooling and APIs that measurably accelerate product development and team efficiency.

What You Bring

• 3+ years of backend engineering experience, with significant ownership over platform or infrastructure components, ideally through the MVP to scale-up phase.
• Proven experience designing and implementing distributed systems, including queueing and large-scale batch processing in production. You own problems end-to-end.
• Familiarity with LLM infrastructure at scale, including token routing, provider failover, and managing real-time vs. async patterns.
• Track record of building internal tooling or APIs that significantly improved team velocity. You treat reliability, observability, and multi-tenant security as first-class concerns.
• Ability to work in person with the team in London five days a week.

Why apply through Dex

This is a rare backend role at a rapidly growing AI company, not one you'll find by cold-applying. We match you to this and other high-calibre roles, ensuring you only consider opportunities that genuinely fit.

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