Lead Full-Stack Engineer in London

ustwo is looking for a Lead Full-stack Engineer to support the delivery of our projects. This is a predominantly full-stack web development role, but extends to supporting mobile app teams, depending on the project. You will work collaboratively to solve difficult problems and build great features in a cross-functional team of engineers, designers, product owners and delivery coaches. With your technical expertise you will manage project priorities, deadlines and deliverables. You will help design, develop, test, and deploy software solutions. You will work on projects that make a meaningful impact for our clients, their customers, and the world.

How You’ll Spend Your Time:

• You will design, develop, test, deploy, and improve digital products with a focus on full-stack development: from front-end, to backend, to infrastructure.
• You’ll work with delivery coaches and product/design leads to ensure we’re building high-quality products as well as delivering the project on time, on budget.
• You’ll be expected to drive technical direction in projects and assure they meet scalability, robustness and security requirements.
• You will be responsible for the technical approach to problems, and getting the team aligned on a technical vision.
• You will be hands-on with projects, getting deep into code and be looked upon as a senior authority in software development.
• You will also spend lots of time working with client teams to agree on technical approach and constraints, interacting with client stakeholders, and socialising tech designs to varied audiences.
• As a tech lead, part of your role is to uplift the tech team through mentoring, working collaboratively, and possibly line management if it’s a good fit for all involved.
• You’ll bring new ways of working and approaches to building solutions.
• You will be accountable for the technical delivery of the project by the team.

What We’re Looking For:

• Excellent communication skills.
• Wide experience building secure, reliable, performant, and usable web applications.
• You can identify and apply the best design patterns for the problem at hand.
• Significant experience crafting the highest-possible quality user interfaces using HTML/CSS/JS.
• Significant experience of JS/TS/Node or at least one other server-side language.
• Experience deploying, securing, scaling, and monitoring in the cloud with deep experience of at least one of AWS, Azure, or GCP.
• Experience working with infrastructure as code (using tools like Terraform).
• Awareness of modern front-end frameworks/libraries (React, Vue, Next, etc), with deep experience in at least one.
• Experience with databases (SQL / NoSQL / real-time, etc.)
• Experience of API design and API integration / testing / implementation (i.e. GraphQL, REST, etc.)
• Experience with version control and an opinion on its proper use.
• Experience with automated testing (e.g. unit, integration, API, etc.)
• Experience with creating and maintaining CI/CD pipelines and typical integrations.
• Experience designing for the most common non-functional requirements (NFRs) including performance, reliability and availability, usability and accessibility, security, maintainability, scalability, observability, portability, and compliance (e.g. GDPR).
• Experience with AI-assisted development: comfortable delivering quality code using CLI or editor-based LLM agents; using MCP servers; maintaining up-to-date documentation; defining shared rules; and establishing team-wide conventions.
• Experience working within agile frameworks such as Scrum / Kanban, leading agile ceremonies, and most importantly, embodying the agile principles.

Nice To Have Experience:

• Knowledge of latest enhancements in core web technologies along with browser support – to enable good recommendations for our implementation choices.
• Knowledge of CSS preprocessors (PostCSS, Stylus, SASS) and CSS patterns.
• Experience leading the development of accessible, WCAG-compliant user interfaces.
• Interest in systems architecture, and demonstrated experience using diagrams to visualise complex ecosystems (or application designs) for varied audiences.
• Experience with TDD and/or BDD and automating this using a framework (Mocha, Jest, Cucumber, Rspec, Capybara, Selenium, etc.).
• Experience working with containerized services and orchestration, although if you don’t know how to create and manage them, we’re cool with that!
• Experience delivering AI capabilities: context engineering, vector stores, RAG, on-device AI.

About You:

• You are a hands-on, caring, resilient, patient, results-oriented, and humble person - you get things done.
• You foster community and are interested in bringing people together and making your team a great place to work.
• You’re human, and recognise humanity in others. This means both learning together and being able to speak to others, regardless of level/position, and empathise with their concerns.
• You want to make great products that affect real people’s lives, at scale.
• You have a strong appetite to explore new technologies and share knowledge.
• You have a strong opinion on how to leverage AI effectively both as an individual and across a team.
• You welcome feedback and look to improve project development and understanding.
• You are able to communicate well with non-technical team members or stakeholders.
• You don’t mind swerving out of your lane to take on the most valuable task when it’s needed, whether it’s in your job description or not.
• You are able to work to deadlines and in a fast-paced environment.
• You are a team player.
• You want to work at ustwo!

Job Benefits:

Our full benefits package is available to all permanent and fixed term contract employment. We will also be able to share a benefits deck to showcase local benefits.

Interested but think your experience doesn’t perfectly align with this job description? That’s ok. Research shows underrepresented groups in particular are less inclined to apply for jobs where they don’t meet 100% of the requirements listed. We’d still love to hear from you if you feel passionate about this role! We are committed to creating an inclusive environment for our colleagues, clients, community, and the users of our products. We don’t have all the answers but we’re on a journey, and we are learning together.