Principal Front End Engineer

About Us

Solirius Reply, part of the Reply Group, delivers technical consultancy and application delivery to our clients in order to solve real world problems and allow our clients to respond to an ever-changing technical landscape. We partner closely with our clients, embedding our consultants into their businesses in order to provide a bespoke service, allowing us to truly understand our clients’ needs.

It is this close collaboration with our clients that has enabled us to grow rapidly in recent years and will drive our ambitious future growth plans. We currently have over 300 consultants working with a variety of key clients from both the public and private sectors such as the Ministry of Justice, Department for Education, FCDOS, UEFA, International Olympic Committee and Mercedes Benz; with plans to increase our client base further in the near future.

We operate as a flat organisation and believe in trusting and supporting our team to operate independently. We pride ourselves on being specialists at what we do, making the most of our consultants’ expertise in their fields in order to provide a best-in-class service to our clients. All our consultants have the opportunity to work on a range of different projects, providing a broad range of knowledge on which to develop their careers and progress in the direction they choose.

About you:

You are a motivated and adaptable professional with a strong analytical mindset and a passion for using technology to solve real-world problems. You enjoy working in collaborative, agile teams and take pride in delivering high-quality solutions that make a tangible impact. With strong communication skills and a consultative approach, you’re comfortable engaging with clients, understanding their needs, and translating them into effective outcomes. You understand and align with Solirius Reply Values.

The Role:

We are seeking a highly experienced Principal Front End Engineer to lead the architecture, development, and evolution of our web applications and user experiences. This role combines hands-on technical leadership with strategic influence across engineering, product, and design teams.

As a Principal Engineer, you will define front-end standards, mentor engineers, drive platform scalability, and ensure exceptional performance, accessibility, and usability across our products.

Requirements

Key Responsibilities:

• Lead the design and implementation of scalable, maintainable front-end architectures
• Drive technical strategy and establish engineering best practices for UI development
• Build high-performance, responsive, and accessible web applications
• Collaborate closely with Product, Design, and Back-End Engineering teams to deliver exceptional user experiences
• Own and evolve shared component libraries, design systems, and front-end tooling
• Improve application performance, reliability, observability, and developer experience
• Mentor senior and mid-level engineers through technical guidance, code reviews, and architectural leadership
• Evaluate and introduce modern front-end technologies and frameworks where appropriate
• Influence roadmap planning and technical decision-making across multiple teams
• Champion testing strategies including unit, integration, visual regression, and end-to-end testing
• Ensure adherence to accessibility, security, and compliance standards
• Lead incident response and root cause analysis for front-end production issues

Key Skills/Experience:

• Software engineering experience with significant focus on front-end development
• Deep expertise in JavaScript, TypeScript, HTML5, and CSS3
• Extensive experience with modern frameworks such as React, Next.js, Vue, or Angular
• Strong understanding of front-end architecture patterns, state management, and component-driven development
• Experience building and scaling design systems and reusable UI platforms
• Strong knowledge of web performance optimisation techniques
• Expertise in accessibility standards (WCAG) and responsive design
• Experience with testing frameworks such as Jest, Cypress, Playwright, or Vitest
• Strong understanding of CI/CD pipelines and modern development workflows
• Proven track record of leading large-scale technical initiatives
• Excellent communication and stakeholder management skills

Preferred Qualifications:

• Experience with micro-frontends or distributed front-end architectures
• Familiarity with cloud platforms such as AWS, Azure, or GCP
• Experience with GraphQL and modern API integration patterns
• Knowledge of observability and monitoring tools
• Experience leading globally distributed engineering teams
• Contributions to open-source projects or technical communities

Benefits

What We Offer:

• Competitive Salary
• Bonus Scheme
• Private Healthcare Insurance
• 25 Days Annual Leave + Bank Holidays
• Up to 10 days allocated for development training per year
• Enhanced Parental Leave
• Paid Fertility Leave (5 Days)
• Statutory & Contributory Pension
• EAP with Help@Hand
• Gym Membership Benefits
• Flexible Working
• Annual Away Days/Company Socials

Equality & Diversity:

Solirius Reply is an equal opportunities employer. We are committed to creating a work environment that supports, celebrates, encourages, and respects all individuals and in which all processes are based on merit, competence and business needs. We do not discriminate on the basis of race, religion, gender, sexuality, age, disability, ethnicity, marital status or any other protected characteristics.

Should you require further assistance or require any reasonable adjustments be put in place to better support your application process, please do not hesitate to raise this with us.