Senior Software Engineer (Backend) in London

About ExTrac

ExTrac is a decision intelligence company used by governments, defence organisations, financial institutions, and corporates operating in complex, fast-moving environments. Our capabilities fuse curated data sources, domain-specific AI, and deep human expertise to transform information overload into clear, actionable foresight. Our ambition is to become the analytical backbone that organisations rely on when geopolitical uncertainty becomes an opportunity or a strategic risk.

The Role

We are looking for a Senior Software Engineer to join ExTrac's engineering team to help build and operate the services and pipelines the platform runs on. ExTrac takes a continuously ingested, multi-source corpus and turns it into products analysts use to make decisions under time pressure. You will be responsible for building and running the backend microservices that make that possible: services and databases that expose curated data through APIs, run search and aggregation over large indices, hold application state, and keep the whole thing fast and correct as volume and customer count grow.

The work is broad by design. In a single quarter it spans API and service design, search and database performance, long-running data pipelines, cloud infrastructure, and the deployment tooling underneath all of it. You will own services end to end across a Go and Python codebase, working alongside the AI team who build our analytical and agentic features, the frontend team who build the web and mobile interfaces, and the analysts and product managers who define what gets built.

What the job involves

• Service design and delivery
  • Take an ambiguous problem, gather requirements, write a technical design, and ship to production with minimal oversight.
  • Own services end to end, including consolidating or decommissioning what they replace.
  • Contribute to and lead system design and architecture decisions.
  • Design APIs used by both internal teams and customers, and hold them to clear contracts and sensible versioning as the number of consumers grows.
  • Treat the storage layer as a design concern rather than an implementation detail: schema, indexing strategy, and access patterns. Establish clear access patterns and boundaries.
• Production engineering
  • Develop Go and Python-based microservices to support data collection, processing, and querying.
  • Hold services to production standards for latency, cost, and reliability, with the instrumentation in place to know when they are not meeting them.
  • Build and operate high-throughput data streaming pipelines and work on improving scalability, robustness, and latency.
  • Optimise databases and index performance where it is the constraint on product behaviour.
• Working with analysts, product, and the ML team
  • 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 platform work.
  • Partner with the AI and frontend teams to deliver cross-functional features, solving the engineering, performance, and reliability problems that sit outside of their scope.
  • Improve the shared foundations other engineers depend on: deployment pipelines, service templates, observability, and the environments their work runs in.

You should apply if

• You have built and operated production backend systems. You will spend your time working on and owning Go and Python services, databases, and APIs, and you know the difference between something that works on a laptop and something that holds up under production load, latency, and cost.
• You can operate with a high degree of autonomy. You will be trusted to lead projects, make decisions, and drive outcomes. We work on open-ended problems with no established answer, and when the obvious approach fails you generate alternatives rather than stopping.
• You do not trust a change until you have measured it. Reaching for the profiler, the trace, or the metric is instinct rather than afterthought.
• You treat quality, security, and observability as engineering fundamentals rather than optional extras, and you make the case for addressing technical debt rather than living with it.
• You raise the bar for the engineers around you in ways they would recognise: pairing on problems outside your own project, leaving reviews people learn from, and writing things down for the next person.
• 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.

Where this role can take you

• Deepen your ownership. Strong performance means ownership over larger sections of the platform, more architectural say over how our services evolve, and more influence over which problems we take on.
• Breadth rather than a narrow track. The work follows the problem, which means service design one month and pipeline or infrastructure work the next. Engineers here have the opportunity to build depth across several areas rather than being funnelled into one.
• Progress without changing track. ExTrac values the IC and management paths equally: Staff Engineer and Engineering Manager sit at the same level, and taking on reports is not the price of progression.

Requirements

• Due to the nature of our work and the clients we support, applicants must be eligible to obtain UK security clearance. We are currently only able to consider applicants who are nationals of a NATO member state, Australia, or New Zealand.
• 4+ years of professional software engineering experience, with demonstrated ability to stand up production-grade services and experience owning features end to end.
• Proficiency in building microservices using Go or Python.
• Solid understanding of distributed systems, databases, and software engineering patterns.
• Experience with cloud infrastructure and infrastructure as code, and with the CI/CD pipelines around them.
• Strong communication and collaboration skills. Comfortable writing clear technical documentation and discussing requirements with colleagues from engineering and the wider team.
• Breadth across the stack: improving deployment pipelines, understanding database behaviour, and a genuine interest in security engineering.
• An interest in how the product is actually used, and a willingness to take analyst feedback into requirements discussions rather than treating requirements as someone else's problem.

Desirable

• Currently working with Go-based microservices.
• Experience with Elasticsearch and PostgreSQL.
• Experience with streaming or event-driven pipelines.
• Experience with feature flags and trunk-based development. Features land close to weekly, and individual deploys go out several times a day across several projects.
• Experience operating multi-tenant systems where data isolation is a hard requirement.
• Experience working in software for defence, government, or other compliance-constrained environments.

Interview Process

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

Benefits

• Competitive salary based on skills and experience.
• A generous benefits package, including Private Medical Health Insurance and enhanced pension contributions.
• Enhanced parental leave and a workplace nursery scheme.
• £500/year education budget with more expensive items (like conferences) covered with manager approval.
• 33 days of leave across the year inclusive of bank holidays.
• Flexible working. The team is typically in our central London office two days a week, and you are welcome to come in up to five.

ExTrac AI provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, colour, religion, sex, national origin, age, disability, genetic information, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.

ExTrac AI is committed to a fair and transparent hiring process. We confirm that this advertisement is for an active, existing open role within our organisation. Please be advised that we may use artificial intelligence-driven tools to assist our recruitment team in screening, assessing, and selecting candidates for this position but all hiring decisions will be made by a member of our team.