Product Engineer (Backend) - Senior/Staff (up to £180k)

Dex; Greater London; Híbrido; GBP 110.000 - 180.000; Jornada completa

Descripción de la vacante

Dex is recruiting for a London-based, hybrid role in a trusted partner company. You will join one of three engineering squads as a backend-focused Product Engineer, shaping architecture, production metrics, and scalable workflows for AI agents.

The role emphasizes serious distributed systems work, concurrency control, and end-to-end delivery. You should have a proven track record at Senior or Staff level in distributed backend design, with FP experience and comfort in languages like Elixir,

Formación

• Proven track record designing and operating distributed backend systems under high concurrency.
• Strong understanding of functional programming concepts and FP languages.
• Ability to balance performance, reliability and product requirements.

Responsabilidades

• Architect high-throughput pipelines with strong traceability and auditability.
• Address concurrency and multi-tenant scheduling at scale.
• Build deterministic audit engines linking outputs to source data.
• Define guardrails, test gates, and reliability boundaries for production systems.
• Own features end-to-end from discovery to production monitoring.

Conocimientos

Senior backend design

Distributed systems

Concurrency & latency

Functional programming (Elixir bonus)

Herramientas

Elixir

Scala

Clojure

Haskell

Descripción del empleo

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.

Most generative AI tools stall at toy demos because regulated enterprises cannot afford unverified answers. This London-headquartered scale-up cracked production adoption by turning document-dense underwriting, due diligence, and risk operations into fully auditable AI workflows. Backed by premier global VCs and foundational AI researchers, their platform has reached multi-million ARR and grown over 20x in the past year alone.

You will join one of three engineering squads in London as a backend-leaning Product Engineer, owning core capabilities from architecture to production metrics. This is not prompt tinkering or thin API wrapping; it is serious distributed systems work tackling extreme concurrency, fair tenant scheduling, and real-time model orchestration. You will operate as an orchestrator of AI agents to accelerate delivery, but you are expected to understand the machine underneath and ship production code multiple times a day.

The work

• Architecting high-throughput processing pipelines capable of moving up to a million documents concurrently without dropping state or losing traceability.
• Solving concurrency, fair multi-tenant scheduling, and token optimisation challenges across massive volumes of parallel model calls.
• Building deterministic audit engines that trace every workflow output and reasoning step back to the source text for human-in-the-loop verification.
• Setting the architectural guardrails, automated test gates, and reliability boundaries while increasingly directing AI agents to generate code.
• Owning features full-cycle alongside product and design, from initial discovery and schema design to production deployment and metric tracking.

What You Bring

• Proven track record at Senior or Staff level designing and operating distributed backend systems under serious concurrency, volume, and latency constraints.
• Solid grasp of functional programming paradigms; experience with Elixir is a bonus, but deep expertise in languages like Scala, Clojure, or Haskell translates directly.
• Deep fundamental software engineering depth: you learned to architect resilient systems before AI wrote code, and you can inspect, profile, and debug what is happening under the hood.
• Product-first judgment: you navigate ambiguous customer requirements, debate architectural trade-offs openly, and measure success by business impact rather than lines of code committed.
• Based in or able to work hybrid from London.

Why apply through Dex

The market is flooded with AI wrappers, making it difficult to pinpoint teams handling genuine distributed scale and paying real technical debt. Applying through Dex cuts through the noise, matching you directly to vetted engineering seats with upfront visibility into team calibre, technical architecture, and compensation. One application gives you access to this London squad and comparable high-signal roles without cold outreach.