Backend Engineer — AI Infra & Scalable Systems (London On-site)

Dex; Greater London; On-site; GBP 90,000 - 120,000; Full time

Job summary

Dex, in London, is seeking a backend engineer to own core platform components and scale large-scale batch processing for an enterprise-ready AI operating system. You will work on the LLM gateway, token routing, and multi-tenant security, delivering reliable infrastructure from day one.

You will join a lean team, collaborating closely with peers in person five days a week in London, taking ownership from MVP through scale-up and shaping critical backend foundations for high-scale production

Qualifications

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

Responsibilities

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

Skills

Backend engineering

Platform ownership

Distributed systems

LLM infrastructure

Reliability & observability

Internal tooling / APIs

In-person collaboration

Job description

Dex, in London, is seeking a backend engineer to own core platform components and scale large-scale batch processing for an enterprise-ready AI operating system. You will work on the LLM gateway, token routing, and multi-tenant security, delivering reliable infrastructure from day one.

You will join a lean team, collaborating closely with peers in person five days a week in London, taking ownership from MVP through scale-up and shaping critical backend foundations for high-scale production