Principal Software Engineer

The NHS workforce is broken. Clinician burnout is at an all-time high. The UK's temporary staffing bill has hit £8 billion. The way healthcare organisations manage and schedule their workforce is failing.

We built Lantum because we want to change that. Our Connected Scheduling™ platform helps healthcare organisations manage their workforce more effectively, giving clinicians more control over how and when they work and giving organisations the tools to staff more efficiently. Over 50% of UK GP practices and 30% of UK Trusts already rely on us. We've saved the NHS millions and helped thousands of clinicians improve their work-lives. We're rebuilding how this industry operates and we're looking for people who want to be part of that.

Lantum’s market-leading Connected Scheduling™ platform keeps the NHS staffed. In Primary Care, it rosters clinicians across more than 2,000 organisations, with digital staff banks and a marketplace of 30,000 vetted clinicians. In Secondary Care, In-Genius™ builds optimal rotas for resident doctors, In-Flight™ manages them day to day, and In-Check™ Compliance (formerly DRS) audits every worked hour against working-time legislation and NHSE standards so that payroll is exact.

About the Role

As our Principal Engineer, you will lead all core software engineering work across the entire Lantum platform and service architecture to scale Lantum’s next stage of growth. You will work alongside our heads of AI/ML and product, healthcare domain experts, and Operations teams while staying hands-on to ship code to production yourself. The role is a true full-stack - “any-stack” - one, and covers back-end, front-end, architecture, infrastructure, DataOps, AI SDLC, and security realms and disciplines.

Responsibilities

As a Principal Engineer,

● you own core, end-to-end software engineering processes and infrastructure;

● you ensure that our existing core revenue-generating systems run without interruption under strict SLAs while optimising them, expanding their capabilities, and increasing cross-connectivity across our multi-product and services platform;

● you protect sensitive operational healthcare data and financial information (as both assets and end-to-end data flows), and ensure that all systems, services, and artefacts meet strict regulatory criteria pertaining to security, observability, traceability, and verifiability;

● you lead, support, and guide other engineers while synchronising build horizons with our wider multidisciplinary team;

● design, build, operate, and secure agentic workflows, multi-agent systems, guardrails, security-first agentic architectures and topologies, and context flows;

● you operate, optimise, and govern coding agents, software factories, and the use of wider AI tooling to enable reliable and precise AI FinOps and effective AI governance; and

● you operationalise and optimise the next stage of Lantum’s AI-native software development lifecycle that combines agentic loops with rigorous verifiability, observability, testing, and review processes.

About You

The Principal Engineer role is ideal for an engineer archetype who

● has a true full-stack (“any-stack”) and polyglot mindset;

● has a track record in building successful, mission-critical systems in non-trivial domains such as healthcare, finance, insurance, aviation, cybersecurity, and the like;

● has (ideally) operated in both agile start-up environments and large(r) formal, regulated enterprises;

● is an inspirational tech lead, leader, and catalyst, with a passion for guiding, supporting, and growing engineering organisations; and

● is a true builder with deep passion for robust end-to-end software engineering, with deep expertise in the traditional praxis, and, ideally, the new, emerging AI SDLC and agentic praxis.

Requirements

Direct, demonstrable expertise and a track record in:

● owning (designing, building, deploying, scaling, optimising, operating, and maintaining) and signing off non-trivial systems, services, platforms, and artefacts which satisfied heavy, long-horizon SLAs, SLCs, and SLOs, and met mission-critical client and regulatory requirements around stability, resilience, reliability, scalability, precision, quality, security, safety, observability, auditability, and verifiability, and the like;

● provisioning, operating, and optimising fully cloud-native, cloud-first architectures and estates (must-have) and local, on-premise infrastructure (desirable);

● designing, implementing, and sustaining robust, secure tech estates and zero trust architectures, auditable data pipelines, supply chain security, and organisation-wide SecOps and risk management processes that met formal security standards, certification, and verifiability;

● leading multidisciplinary full-stack engineering teams, covering end-to-end back-end, front-end (incl. mobile), architectures, DevOps, infrastructure, DataOps, and SecOps (or a majority thereof);

● mentoring, line-managing, and supporting engineering colleagues, and growing engineering organisations;

● supporting and synchronising development streams and deliverables with ML scientists, data scientists, product managers, or operations teams; and

● effective interaction and interfacing with senior management and domain experts in both technical and nontechnical domains.

Additional Exposure

Exposure to the following is highly desirable:

● MLOps, data science, data analytics, classical ML, experiments, evaluation, and evidence-based optimisation; and

● HealthTech, healthcare systems and products, and the wider NHS ecosystem.

Tech Stack

Demonstrable expertise in a good majority of the following:

● advanced core Linux skills and administration;

● languages and VMs: advanced Python (must-have) plus ideally substantial JVM (Java or Scala), .NET (C#), Rust, or Go expertise; Typescript and Javascript (must-have); Node.js (ideal);

● APIs: RESTful APIs (must-have); GraphQL (desirable); MCP (desirable) or A2A (desirable);

● web frameworks (Django (must-have)) and front-end frameworks (React (must-have), Blazor (desirable));

● mobile frameworks: React Native (highly desirable);

● databases: both SQL (Postgres (must-have), SQL Server (desirable)) and NoSQL (MongoDB (desirable));

● cloud platforms, infrastructure, IaC, containerisation, and compute: AWS (must-have); Azure (desirable); Terraform (must-have) and policy as code; Docker (must-have); serverless architectures; sandboxes and enclaves;

● GitOps and CI/CD pipelines; and

● GenAI, LLMs, and agentic frameworks, APIs and SDKs (such as Anthropic, OpenAI, Google Gemini, Jev, LangChain, LangGraph, PydanticAI); agent sandboxes and enclaves; agent harnesses; and agent memory substrates.

Education

● A degree in a STEM subject: an undergraduate degree (must-have), a postgraduate degree (highly desirable), or a PhD (highly desirable).

Interview Process

● Introduction and Meet Your Manager: We’ll book you in for a first interview with your potential future manager, so you can learn more about what the role is holistically and understand our technical focus, while we get a deeper understanding of you as an engineer as well as your experience, career trajectory and plans, and interests.

● T-1 Tech Fundamentals: This is a more formal, purely technical and technological session with Lantum’s senior experts with a software engineering, AI, ML, and data science background. We will go through fundamental engineering