Platform Engineer - MIThe Security Service - HEO

Location

London

MI5 keeps the country safe from serious threats like terrorism and attempts by states to harm the UK, its people, and way of life. We carry out investigations by obtaining, analysing, and assessing intelligence, and then work with a range of partners including MI6 and GCHQ, to disrupt these threats. Through our protective security arm, we provide advice and guidance to government, businesses, and other organisations on how to keep themselves safe.

A role in MI5 means you'll do unique and challenging work in a supportive and encouraging environment, making a real difference to UK national security.

As a Platform Engineer, you'll design, develop and operate platforms that give developers the tools they need to build critical technology that helps keep the country safe. Joining MI5 offers the opportunity to contribute to a growing technology capability while being part of an expanding engineering workforce, helping to enhance platforms and products delivered across the organisation.

Day to day, the role involves building developer tooling, managed services, and automation, along with self‑service solutions. Infrastructure‑as‑code is used to ensure consistency and reliability across cloud and on premise environments, enabling teams to move quickly with confidence.

A significant part of the role centres on working closely with our product teams, understanding pain points, prioritising what matters most, and shaping solutions that meaningfully improve the developer experience. The outcome is streamlined workflows, reduced friction, and more time for engineers to focus on delivering solutions to meet MI5's outcomes. You'll play a key part in contributing to our engineering community by sharing best practice standards, patterns, and establishing clear and consistent approaches that teams can adopt with confidence.

When issues arise, you'll get stuck in, troubleshooting platform problems and improving reliability, usability, and observability, while feeding those insights back into better design. Sharing knowledge across teams will be a big part of the role, as will helping to build a consistent, collaborative engineering culture. You'll also support other engineers, helping them build confidence and develop their skills.

We know that platform engineering evolves constantly, and the quality of this role depends on keeping pace with it. As a result, there is a regular protected time to horizon scan, research emerging trends, and pursue training or certifications relevant to your career.

A natural problem solver, you enjoy tackling complex challenges and turning them into practical solutions. Experience may come from working as a Platform or Dev Ops Engineer across a range of technologies and customer environments, or from a Software Engineering background with demonstrable experience in solving platform and infrastructure‑related challenges in current or recent roles.

An understanding of the software development lifecycle in an enterprise or commercial environment is essential, alongside familiarity with design patterns and secure coding practices.

Working closely with engineers and technologists, this role focuses on understanding challenges and shaping effective platform solutions. Confidence communicating with both technical and non‑technical audiences is important, particularly when explaining ideas clearly, aligning on priorities, and building trust across teams.

You'll be comfortable working independently with a high level of autonomy, making pragmatic decisions and seeing work through from problem to solution. Being proactive in seeking support from senior engineers and leaders when needed, along with a willingness to learn and grow, is also important.

Proficiency in at least one modern programming language, such as Node.js, Python, or Java, is expected along with experience in core engineering practices including TDD, CI/CD pipelines, cloud services, and agile methodologies. Familiarity with infrastructure‑as‑code tools such as Terraform is also important.