AI Software Engineer

Who you are

• You have built and worked on production backend systems, and you want to keep doing that. You will spend more of your time in Python and Go services, databases, and APIs than in a prompt file, and you know the difference between something that demos well and something that holds up under production load, latency, and cost
• You can work independently on well-defined problems, and know when to flag ambiguity or ask for input rather than guessing. When the obvious approach fails, you look for another one before escalating
• You are curious about agentic frameworks and comfortable working without one. Experience with them is useful, but we build most of our own orchestration, because off-the-shelf abstractions have not survived our requirements around evaluation, control, and production performance
• You can take a recent technique or paper, help spike an implementation, and reason clearly about whether it is worth taking further
• You do not trust a change until you have measured it. Reaching for the evaluation is instinct rather than afterthought
• You actively seek feedback and act on it, and you look for opportunities to pair with and learn from the engineers around you
• You want to work on things that matter. Our software sits underneath decisions taken by governments, defence organisations, and institutions operating where being wrong or late carries real consequences
• Due to the nature of our work and the clients we support, applicants must be eligible to obtain UK security clearance
• 2+ years of professional software engineering experience, with demonstrated ability to build and ship production-grade services with solid test coverage, and experience owning features or components end to end within a larger system
• Proficiency in building services in Python, with working knowledge of Go or the ability to pick it up quickly
• Some exposure to agentic systems, LLM applications, or retrieval running in production, or clear evidence you would pick them up fast
• A good understanding of distributed systems and databases, including writing asynchronous code that performs under load
• Experience with cloud infrastructure and the CI/CD pipelines around it
• Comfortable working with trunk-based deployment
• Comfortable being handed a symptom rather than a diagnosis. Given a suspected memory leak, you would profile it, find the cause, and fix it, asking for support when you get stuck
• Able to take a well-defined requirement and scope a technical approach from it, asking clarifying questions up front rather than assuming. You communicate clearly in writing and can produce documentation colleagues can follow, and you look for a way through rather than concluding something cannot be done
• Breadth and curiosity across the stack: an interest in deployment pipelines, database behaviour, security and AI guardrails, and in validating analytical outputs and feeding analyst feedback into requirements. You pick up unfamiliar tools quickly rather than needing prior expertise in a specific one
• Experience with retrieval systems and large-scale vector database performance (Elastic)
• Experience with graph or network analysis at scale
• Experience building retrieval or analysis that works across multiple languages
• Experience with infrastructure as code, streaming pipelines, and search infrastructure
• Experience operating multi-tenant systems where data isolation is a hard requirement
• Experience working in compliance-constrained environments. A significant upcoming project is making our systems work within FedRAMP environments

What the job involves

• We are looking for a Software Engineer to join ExTrac's AI team, building Co-Analyst and the analytical AI features around it
• Co-Analyst is a user-facing multi-agent system that works alongside intelligence analysts to research and write reports
• A planning loop decomposes an analyst's question, fans work out to sub-agents, and assembles the results into a report where every claim traces back to the chunk of source it came from
• Underneath sits hybrid retrieval over a large unstructured corpus: analyst intent translated into structured filters, combined with keyword and dense vector search, across multiple languages and media types
• The agent work is the centrepiece but not the whole job
• In a single quarter the work spans agent orchestration, retrieval, graph analytics, and long-running streaming pipelines, alongside the services and databases underneath them
• You will own well-defined features and components end to end across a Python and Go codebase, working alongside senior engineers who set technical direction, the data team who own the ingestion pipelines, and a research-focused ML team who train and evaluate the models we integrate and serve
• The loop is short: product brings an idea, often recent and unproven, and our job is to spike an implementation and take it to a production feature
• New features land close to weekly
• This hire exists to add capacity on the AI team's hard problems: an engineer who can independently deliver well-scoped features and components, and who is building towards owning more of the system end to end
• Build and improve components of the agent loop itself: context assembly, tool selection, and sub-agent orchestration, with guidance from senior engineers on the team
• Build the analytical AI features that sit alongside it, from network construction through to the summaries analysts read
• Help prove that changes are improvements, running experiments against live analyst traffic behind feature flags
• Contribute to agreeing what "better" means for a capability, and flag honestly when the evidence says a promising approach is not working
• Work with embeddings as more than a retrieval concern. The same vectors drive network construction and community detection
• Work within a model-agnostic design, swapping models and embeddings on the back of the ML team's evaluations rather than being locked to one
• Take a well-defined problem, clarify requirements with your lead or a senior engineer, and ship it to production with regular check-ins rather than close oversight
• Own features and components end to end within a single system, contributing to system design and architecture discussions and taking on more of the design work as you build context
• Build and maintain APIs used by internal teams and customers, following established contracts and versioning conventions
• Work with the storage layer as a design concern rather than an implementation detail: schema, indexing strategy, and access patterns, across relational, document, and vector stores
• Build and operate supporting services across Python and Go, with growing ownership of design, deployment, and operations as you build track record
• Help hold agent workflows to production standards for latency, cost, and reliability, in a system where non-determinism is a given
• Build and operate long-running streaming pipelines, including the caching and recovery behaviour that makes them survivable
• Work directly with the analysts who use our products, turning what they hit in practice into changes in the system
• Iterate quickly against a live stream of product requests, flagging where they collide with longer-horizon capability work
• Partner with the ML team on agentic approaches, helping take proven concepts to production and working through the engineering, performance, and reliability problems a research implementation does not have to
• Help integrate and serve the models they train, and contribute to the production infrastructure their evaluation frameworks run on

The application process

• Initial Intro Interview with Hiring Manager - 30 Minutes
• Technical Assessment - 1 hour
• Competency-based Interview - 1 hour
• Founder interview - 30 Minutes

Benefits

• Flexible working: work where you work best, with the opportunity to spend 2-5 days a week working with the team in our central London office
• An annual individual learning and development budget of £500
• A generous private healthcare package
• Cycle to work scheme
• 33 days of annual leave
• Sabbatical leave offer
• Enhanced pension contributions
• Enhanced parental leave
• Workplace nursery scheme
• Regular team lunches and socials
• An annual individual learning and development budget
• A generous private healthcare package
• On-target earnings (OTE) structure tied directly to customer outcomes
• A role that combines mission-driven purpose with cutting-edge technology in a fast-growing company.