Senior Full Stack Engineer

Wessex Water Services; Bath; On-site; GBP 70,000 - 110,000; Full time

Benefits offered by this job

Pension contribution up to 20%

Career development opportunities

25 days’ holiday rising to 28 with len

Healthcare package

Life assurance

Employee car salary sacrifice option

Referral bonus

Job summary

YTL UK is seeking a Senior Full Stack Engineer to drive end-to-end delivery from data and backend services to user interfaces. You will be hands-on, writing production-quality code, conducting peer reviews, and validating solutions through automated tests.

In a fast-paced, AI-first engineering team, you will own significant portions of delivery, improve harness tooling, and stay ahead of industry trends while ensuring reliability and security across the stack.

Qualifications

• Hands-on delivery across data, backend services and UI components.
• Strong Python and JavaScript/TypeScript coding skills.
• Experience with Azure and Azure DevOps in a modern CI/CD setup.
• Awareness of security, observability and test automation.
• Familiarity with AI-first, agentic delivery approaches.

Responsibilities

• Design, build, test and maintain scalable software services.
• Own end-to-end delivery from data pipelines to user interfaces.
• Conduct peer reviews and validate solutions with automated tests.
• Maintain reliability, performance and maintainability of ship-ready code.
• Stay current with AI tools, agents and industry best practices.

Skills

Full-stack engineering

Azure & Azure DevOps

Python

JavaScript/TypeScript

CI/CD pipelines

Infrastructure as code

Security & observability

AI-first, agentic delivery

UI/UX awareness

Testing & QA

Tools

Azure DevOps

CI/CD tooling

IaC tooling

Observability tools

Job description

As our new Senior Full Stack Engineer, you will play a key role in the end-to-end delivery of products and services, owning a significant portion of each delivery from data and backend services through to user-facing interfaces. Working within a fast-paced, AI-first engineering team, you will help deliver high-quality, scalable, and supportable solutions at speed.

This is a hands-on engineering role where you will actively design, build, test, and maintain software services. You will be responsible for writing production-quality code, conducting peer code reviews, validating solutions through automated and manual testing, and ensuring the reliability, performance, and maintainability of everything you ship.

What you'll do

In this varied role, you will:

• deliver services end to end - data through to interface, with their tests and evaluations - so that the team ships to done inside the time box
• build from harness scaffolding, rules files and the skills library so that the floor is inherited by default
• own the output of agentic workflows, whoever or whatever wrote it, so that the team ships work it understands and can stand behind
• keep progress legible and raise blockers and scope risk the day they appear so that a fixed time box is protected by honest, early signalling
• pay down debt and clear logged exceptions with the Architect at cooldown, and feed build reality into the harness backlog, so that every bet starts from a higher floor than the last
• take on harder work and a growing share of review cycle on cycle, so that capability deepens and delivery does not bottleneck on the leads
• proactively track industry trends, emerging tools and agentic engineering practice, and self-initiate the learning needed to apply them - trialling promising techniques and approaches in cooldown and sharing what works back into the harness, rules files and skills library.

What you’ll need

We are looking for:

• strong, current full-stack engineering capability with hands-on delivery in an Azure and Azure DevOps (ADO) ecosystem
• fluent practical coding in Python and JavaScript/TypeScript, working comfortably across back-end services, front-end interfaces and automation scripting
• consideration for UI/UX best practices and emerging design trends
• the ability to take a slice from data through to interface, including its tests and evals, without waiting for it to be specified in detail
• comfortable building within CI/CD pipelines and infrastructure-as-code, to the secure, observable and tested defaults the pipeline enforces
• sound grounding in security, observability and test and evaluation automation, enough to leave a deliverable operable by a team that did not build it
• practical experience of AI-first, agentic delivery - working from rules files, known-good templates and a curated skills library, and writing evals for AI-generated output
• sound judgement on where agents help and where human design must come first, with the discipline to pace throughput to comprehension
• habit of honest, early signalling on progress, blockers and scope, and of contributing improvements back into shared tooling and standards
• a working knowledge across multiple AI tools and models, with the judgement to select the appropriate tool/model based on the development task, complexity, security requirements and expected outcome
• a strong prompt and context engineering skills, including creating effective instructions, rules and contextual information appropriate to the goal
• experience with agentic software engineering workflows, including orchestrating AI agents to perform multi-step development activities while maintaining appropriate human oversight.

What you’ll receive

• A combined pension contribution of up to 20%.
• Career progression and professional development opportunities.
• 25 days’ holiday rising to 28 with length of service.
• The opportunity to sell up to five days of holiday every year.
• The opportunity to buy up to ten days of holiday each year (subject to conditions).
• A healthcare package that allows you to claim back healthcare costs.
• Life assurance of up to eight times your salary.
• The opportunity to lease a new electric car through salary sacrifice (subject to conditions).
• Cashback and discounts from more than 3,000 retailers.
• One paid volunteering day each year.
• Enhanced family leave and pay arrangements.
• Access to an interactive health and wellbeing platform.
• Support from trained mental health first aiders.
• A £1,000 referral fee if you recommend someone who is successfully recruited by us.

Who we are

YTL UK is part of the international YTL Group based in Kuala Lumpur. The UK companies include:

• Wessex Water - one of the top-performing water and sewerage companies in England and Wales, serving 2.9 million people across the South West
• YTL Developments - a major UK developer currently redeveloping a 450-acre former airfield into an award-winning, exciting mix of houses, apartments, schools, commercial space, restaurants and hotels, to make a truly sustainable new community
• YTL Construction UK - a top 20 UK contractor providing fully integrated services to infrastructure, residential, commercial, industry, energy and environmental sectors
• YTL Live - the development and operation of an entertainment complex that includes a 20,000-capacity arena, conferencing and exhibition space
• plus a number of other retail, environmental and specialist businesses.

Our people tell us that YTL UK is a great place to work, which is why so many of them stay with us! You will have a unique opportunity to develop and progress your career within such a diverse group.

We are passionate about diversity and inclusion - with that in mind, all applicants are welcome.

We are delighted to have signed the Armed Forces Covenant and are a Disability Confident Employer.

If you require reasonable adjustments to be made during the recruitment process, please inform a member of our Recruitment team.