Senior Software Engineer (AI Native) in Manchester

We’re looking for a passionate and experienced Senior Software Engineer with an AI Native mindset and a proven track record of commercial delivery of technology value, and a passion for building software with AI agents, to join a new ‘start-up’ division within N Brown. As a member of the Castle project team, you’ll be at the heart of a unique and exciting venture to assemble a new financial services platform. With a background in technology disruption or financial services (preferably retail credit), you’ll leverage your industry knowledge to design key solutions for the platform and direct AI agents to build them. Operating like an independent start-up, within an established organisation, you’ll be completely at home with agile frameworks and will fully embrace iterative, flexible and AI-first delivery approaches.

Job Purpose:

As an AI-Native Senior Software Engineer, you will design, develop, maintain, and deploy complex solutions within Castle using agile development methods, with AI agents doing the majority of the implementation. Rather than writing most code by hand, you’ll define the intent, context and guardrails that let agents deliver high-quality software at pace, while you own the architecture, the review and the outcome. All the while ensuring software quality is embedded and improved, optimising the use of automation tools.

Key Accountabilities:

• Directs AI agents to code, test, document, amend and refactor complex programs/scripts and integration software services, verifying and taking ownership of everything they produce.
• Contributes to the selection of the software development methods, AI agents, tools and techniques.
• Applies agreed standards and tools, encoding them into agent instructions, context and guardrails, to achieve well-engineered outcomes.
• Rigorously reviews agent-generated code and leads reviews of colleagues' work.
• Designs complex software applications, components and modules, breaking work down into well-specified tasks that agents can execute.
• Reviews, verifies and improves own designs against specifications.
• Leads reviews of others’ designs.
• Uses approved tools, techniques and agents for specific deployment activities.
• Follows agreed procedures to identify and resolve issues with applications, using agents to accelerate investigation and fixes.
• Uses application management software and tools to collect agreed performance statistics.
• Continuously improves the team’s agentic development workflows, sharing patterns, prompts and lessons learned.

Your Experience & Education Requirements:

• Demonstrable experience of AI-native software development, using coding agents such as Claude Code, GitHub Copilot or Cursor to deliver production software.
• Skilled in context engineering: writing clear specifications, agent instructions and guardrails, and orchestrating agents across a delivery workflow.
• Strong command of JavaScript/Typescript, with the depth to critically review and correct agent-generated code.
• Hands-on experience with Node serverless microservices, whether it's AWS Lambdas or containerization managed through ECS or similar platforms.
• Familiarity with AWS serverless development and deployment frameworks, including the Serverless framework, AWS SAM, AWS CDK, and more.
• Emphasis on an API-first approach to software development.
• Proficiency in unit and integration testing using frameworks like Jest, and in using tests to verify and constrain agent output.
• Expertise in consuming RESTful services, which includes adeptly handling JSON data.
• Proven experience in continuous integration practices, encompassing source control with Git, building processes (leveraging tools like Azure DevOps, Gitlab, or others), testing, auditing (utilizing tools like SonarQube), and deployment.
• Experience in Agile development methodologies.
• Knowledge of Terraform or a strong willingness to learn Terraform and apply Infrastructure as Code principles.
• Familiarity with Kafka or a strong willingness to learn Kafka and engage with event-driven architecture.
• Understanding of software design patterns.
• Understanding of the risks of AI-generated code, including security, quality and maintainability, and how to mitigate them.

What’s in it for you:

• Hybrid working and flexible start times.
• 24 days holiday (+ 8 bank holidays) with the option to buy an additional 10 days.
• Annual bonus scheme.
• Enhanced maternity and adoption leave.
• Company pension with up to 8% N Brown contribution.
• Mental Health support both internally and externally, including access to our wellbeing champions and counselling services.
• A range of financial wellbeing support.
• Colleague discount across all N Brown brands.
• Onsite café with subsidised rates and local restaurant discounts!
• Life Assurance and Private Medical Insurance.
• Paid volunteer time – all our colleagues can take a full day paid to volunteer for a charity of their choice.

N Brown – who we are and why work for us:

N Brown is a leading UK digital retail platform for clothing, footwear, home and technology, headquartered in Manchester and employing over 1,000 people nationwide. Through our strategic retail brands JD Williams, Jacamo and Simply Be and our unique payments offering, we exist to champion inclusivity and serve the underserved. Our customers are our passion, and we take great pride in delivering products that ensure they can look and feel amazing, without compromising on choice, value and accessibility. We are committed to building a diverse workforce and creating an inclusive environment that values equality for all. Our vision is that by championing inclusion, N Brown will become the UK’s most loved and trusted consumer platform, shaping the future of financial empowerment and personal expression. Diversity, Equity, Inclusion & Belonging are therefore at the heart of our culture.

Ways of Working:

We offer hybrid working which varies across the business depending on the role you’re in. Our Head Office is located in the Northern Quarter in Manchester City Centre. Our working hours are 36.17 per week Monday to Friday. We believe AI will become a standard part of modern professional practice. We are therefore looking for individuals who are open to learning, testing and responsibly adopting AI tools to improve efficiency, insight and impact in their role.

Our Promise to You:

We’re an equal opportunity employer and value diversity. We do not discriminate based on race, colour, national origin, sex, gender, gender expression, sexual orientation, age, marital status, veteran status or disability status.

What happens when you apply to a role at N Brown?

As soon as we receive your application, we’ll send you an email to let you know. We always aim to come back to you as soon as possible with an update, and we really appreciate you taking the time to apply for a role with us.