Senior Software Engineer

Salary: £35,000 - 53,000 per year

Requirements:

• 8 years of experience
• Practical use of, or strong interest in, AI-assisted development tools in a responsible delivery environment
• Experience delivering production software end to end, working closely with stakeholders
• Front-end and back-end development experience
• Experience designing APIs and integrating with enterprise systems and data services
• Good understanding of software design principles and modern engineering practice
• Experience with automated testing and CI/CD
• Experience working with relational databases
• Familiarity with database and caching technologies
• Understanding of secure coding and modern authentication and authorisation
• Experience delivering software in cloud-hosted environments, e.g. Azure
• Ability to work effectively across a mixed technology estate
• Strong communication skills and experience working in collaborative teams
• Experience mentoring others through review, pairing and practical support
• Depending on project requirements, ability to meet UK residency criteria and achieve UK security clearance, such as BPSS and potentially SC

Responsibilities:

• Work closely with senior stakeholders to understand requirements
• Design, build, test, deploy and support software applications, services and reusable components
• Produce pragmatic technical designs that balance quality, security and maintainability
• Work across back-end services, integrations and user-facing applications
• Contribute to engineering standards through code review, testing, CI/CD and documentation
• Design secure APIs and integrations across digital products, enterprise systems and data services
• Work closely with data engineers on APIs, events and data contracts
• Support and mentor others through pairing, review and day-to-day collaboration
• Help make sensible technology choices that keep solutions supportable over time

Technologies:

• AI
• Azure
• CI/CD
• Cloud
• Support
• Security
• ASP.NET
• Angular
• C#
• DevOps
• Django
• Docker
• Excel
• FastAPI
• Kafka
• Kubernetes
• MongoDB
• Podman
• PostgreSQL
• RabbitMQ
• Redis
• Talend
• TypeScript
• Vue

More:

We are Assystem, one of the top three independent nuclear engineering firms worldwide, with over 60 years of experience in highly regulated sectors and 8,000 experts across 13 countries. We are delivering the Assystem Transformation Programme to streamline and harmonise our business operations, redesign our Integrated Management System, and move from document-centric to data-centric ways of working. This Senior Software Engineer role sits within our Digital Excellence Centre UK, where we build secure, maintainable software products and reusable components in a small, senior team. You will work across a varied technology environment with colleagues in the UK, India and, where relevant, France, and contribute to enterprise-wide digital transformation supporting critical infrastructure projects. We offer hybrid working, flexible working hours, a pension scheme with 8% company contribution and 4% personal contribution, 25 days paid annual leave plus bank holidays and the option to buy or sell days, professional fees reimbursement, an employee referral scheme, competitive sick pay, income protection and 3x salary death-in-service cover, free digital gym access, and a 24/7 employee support line for mental health, financial and legal help. We are committed to equal treatment and diversity, and we value different backgrounds, perspectives and contributions.

last updated 36 week of 2026