Senior Backend Engineer - Scalable Platform (London Onsite)

Dex; Greater London; On-site; GBP 85,000 - 120,000; Full time

Job summary

Dex partner company is building an AI operating system for enterprise IT, tackling complex workflows for large enterprises. You will join a lean backend team, owning core platform components and large-scale batch processing while ensuring security and observability.

You'll design the LLM gateway for token throughput and provider failover, and build internal tooling to accelerate product development. This role requires onsite collaboration with the London team five days a week.

Qualifications

• 3+ years of backend engineering experience with ownership over platform components.
• Experience designing and implementing distributed systems including queueing and batch processing.
• Familiarity with LLM infrastructure at scale: token routing, provider failover, real-time vs async patterns.
• Track record building internal tooling or APIs that significantly improve team velocity and reliability.

Responsibilities

• Design and build core backend platform components enabling rapid shipping.
• Develop and scale batch job infrastructure for 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 that measurably accelerate product development and team efficiency.

Skills

Backend engineering

Distributed systems

LLM infrastructure

Internal tooling/APIs

Ownership & accountability

Job description

Dex partner company is building an AI operating system for enterprise IT, tackling complex workflows for large enterprises. You will join a lean backend team, owning core platform components and large-scale batch processing while ensuring security and observability.

You'll design the LLM gateway for token throughput and provider failover, and build internal tooling to accelerate product development. This role requires onsite collaboration with the London team five days a week.