Principal Software Engineer

globalhr; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Competitive salary

Pension scheme

Life Assurance

25 days holiday

Discretionary bonus

Flexible benefits

Enhanced sick pay

Enhanced family leave

Job summary

Raytheon UK is seeking a Principal Software Engineer in London to join our cyber software team. This permanent onsite role involves delivering and deploying critical software across multiple business areas.

You will design and build software using industry best practice, collaborate with stakeholders, and contribute to milestones and continuous improvement. The role requires experience across React, NextJS, TypeScript, Python, Java, REST APIs, and cloud/container tech, with a strong emphasis on

Qualifications

• Experience with modern JS frameworks and REST APIs.
• Familiarity with cloud platforms (AWS/Azure).
• Hands-on with container orchestration and IaC tools.
• Proactive in agile delivery and code reviews.
• Knowledge of databases and search technologies.

Responsibilities

• Develop and deploy critical software across multiple business areas.
• Design software using industry best practices and standards.
• Collaborate with stakeholders and engineers.
• Contribute to milestones and continuous improvement.
• Support technical direction within the team.

Skills

React

NextJS

TypeScript

Python

Java

REST API development

Agile delivery

GitLab

CI/CD

Tools

Docker

Kubernetes

OpenShift

Terraform

Ansible

PostgreSQL

Elasticsearch

OpenAPI/Swagger

Mocha Jest Cypress

Job description

Date Posted: 2026-09-24

Country: United Kingdom

Location: London, London, City of

Position Role Type: Onsite

Principal Software Engineer

Location: London

Permanent

Onsite

Due to the interesting work we do and the sector this team is working in, we require all candidates to hold an active eDV clearance for this role.

About us

At Raytheon UK, we take immense pride in being a leader in defence and aerospace technology. As an employer, we are dedicated to fuelling innovation, nurturing talent, and fostering a culture of excellence.

As a leading defence and aerospace company operating across the United Kingdom, Raytheon UK helps to solve our customers’ toughest challenges. We are a major supplier to the UK government and customers around the globe, providing defence solutions across all domains: land, sea, air, space, and cyberspace. We also provide digital and training transformation solutions to commercial and military customers.

With circa 2000 employees and major facilities operating throughout the UK including Broughton (Wales), Livingston and Glenrothes (Scotland), and Harlow, Gloucester, and Manchester (England); we are committed to investing in British careers and technology development.

Cyber

Our National Security Cyber business delivers mission‑critical solutions that safeguard our national security 24 hours a day, seven days a week. Working in a mature, agile environment, our SCRUM teams work synchronously with our customers to solve some of the toughest digital challenges faced in the world today.

Role & Responsibilities

• You’ll be part of our experienced software dev function, working in a cross‑functional team, delivering and deploying critical software across a variety of business areas.
• Design and build software using industry best practice
• Collaborate with stakeholders and other engineers
• Contribute to the completion of milestones associated with your project
• Contribute to continuous improvement within your team
• Collaborate with your peers on technical direction within your team

Requirements/knowledge (you don't need everything)

• JavaScript frameworks (React, NextJS)
• TypeScript
• Python
• Java
• REST API development
• OpenAPI / Swagger
• Cloud services (AWS or Azure)
• Containerisation & Orchestration (Docker, Kubernetes, OpenShift)
• Infrastructure as Code (Terraform, Ansible)
• Relational Databases (e.g. PostgreSQL)
• Elasticsearch / Opensearch
• Unit testing and automation
• Testing frameworks (e.g. Mocha, Jest, Cypress)
• Experience working in an Agile delivery team
• Use of code repositories (e.g. GitLab); familiarity with branching strategies, pull requests and merge processes

We appreciate you may not be an expert in every area above - we can support with training and development in some areas! Please do make an application and we will identify where we can best support your growth specific to your application.

Benefits

• £: Competitive salary
• Contributory Pension Scheme (up to 10.5% company contribution)
• 6 times salary ‘Life Assurance’ with pension
• 25 days holiday (increasing with service) + statutory public holidays, plus opportunity to buy and sell up to 5 days (37hr)
• Company bonus scheme (discretionary)
• Flexible Benefits scheme with extensive salary sacrifice schemes, including Health Cashplan, Dental, and Cycle to Work amongst others
• Enhanced sick pay
• Enhanced family friendly policies including enhanced maternity, paternity & shared parental leave

Work Culture

• 37hr working week, although hours may vary depending on role, job requirement or site specific arrangements.
• Early 1.30pm finish Friday, start your weekend early!
• Remote, hybrid and site based working opportunities, dependant on your needs and the requirements of the role.
• Up to 5 paid days volunteering each year.
• Flexible working culture focused on output, with more formal flexible working arrangements on request (assessed subject to role) - please highlight any requests to the Talent Acquisition team.

RTX adheres to the principles of equal employment. All qualified applications will be given careful consideration without regard to ethnicity, color, religion, gender, sexual orientation or identity, national origin, age, disability, protected veteran status or any other characteristic protected by law.

RTX adheres to the principles of equal employment. All qualified applications will be given careful consideration without regard to ethnicity, color, religion, gender, sexual orientation or identity, national origin, age, disability, protected veteran status or any other characteristic protected by law.