At a Glance
- Tasks: Lead front-end development, design web applications, and mentor junior developers.
- Company: Join a dynamic tech company focused on innovation and collaboration.
- Benefits: Enjoy competitive pay, flexible leave, and early finish Fridays.
- Other info: Be part of a culture that values learning and career growth.
- Why this job: Make a real impact while growing your skills in a supportive environment.
- Qualifications: 5+ years in front-end development with strong JavaScript, HTML, and CSS skills.
The predicted salary is between 36000 - 60000 £ per year.
As a key member of our development team, you will independently design and implement solutions for JIRA tickets, rigorously test your work across environments, and actively contribute to stand‑ups and day‑to‑day delivery. You’ll support troubleshooting efforts, review and approve pull requests, and drive code quality through enhancement and refactoring ideas shared with our Tech Leads. You will also lead smaller projects with support from technical leadership and contribute to interviewing, onboarding, and mentoring to help grow the wider team. If you’re ready to lead front‑end development on our existing projects, elevate code quality, and help grow the team’s skills, we’d love to hear from you.
You will:
- Lead the design, development, and maintenance of web applications using HTML, CSS, and JavaScript (ES6+).
- Own front‑end architecture and implementation decisions, ensuring code is scalable, maintainable, and consistent across projects.
- Turn UI/UX designs and wireframes into accessible, responsive, and cross‑browser compatible web interfaces.
- Collaborate closely with designers, back‑end developers, project managers, and other stakeholders to shape requirements and deliver high‑quality features.
- Conduct thorough code reviews, providing constructive feedback and helping to maintain coding standards and best practices.
- Mentor and support intermediate and junior developers, guiding them on technical approaches, patterns, and problem‑solving.
- Proactively identify and resolve performance issues, improving load times, responsiveness, and overall usability.
- Debug and troubleshoot complex front‑end issues.
- Promote and maintain clean, well‑documented code, and ensure project documentation is complete and up to date in line with platform guidelines.
- Stay current with front‑end technologies and best practices - and help evaluate and introduce new tools/approaches where they add value.
You have:
- 5+ years of professional front‑end development experience, including work on complex or large‑scale web applications.
- Expert‑level proficiency in vanilla JavaScript (ES6+).
- Strong, hands‑on experience with HTML5 and CSS3, including pre‑processors such as SASS/SCSS.
- Deep understanding of responsive design, cross‑browser compatibility, and mobile‑first development.
- Proven experience designing or working within scalable front‑end architectures and patterns (modular components, separation of concerns, reuse).
- Solid experience with Git and modern collaborative workflows (pull requests, branching strategies, code reviews).
- Demonstrated ability to take ownership of features from concept through to deployment and support.
- Excellent communication and collaboration skills, with the ability to work effectively across disciplines.
- Experience guiding or mentoring other developers and contributing to a positive, learning‑focused team culture.
You may have:
- Experience using jQuery for DOM manipulation and event handling, particularly in maintaining or modernizing existing codebases.
- Strong experience integrating with REST APIs, including error handling, state management, and data flow on the front end.
- Familiarity with SEO‑related front‑end practices (semantic HTML, performance, metadata, structured content).
- Hands‑on experience with front‑end build tools such as Webpack, Gulp, Grunt, or similar (configuration, optimization, troubleshooting).
- Knowledge of front‑end performance optimization techniques, such as bundling, code splitting, minification, and asset optimization.
What we offer:
- Global maternity and parental leave.
- Competitive benefits packages.
- Vacation, compassionate leave, personal/sick days, and flex days.
- Access to online services for families and new parents.
- Early Dismissal Friday’s (off at 3:00 PM local time every Friday).
- 13 affinity groups.
- Internal learning and development programs.
- Enterprise‑wide employee discounts.
Critical Mass is an equal opportunity employer. The Critical Mass Talent Acquisition team will only communicate from email addresses that use the URLs criticalmass.com, omc.com and us.greenhouse-mail.io. We will not use apps such as Facebook Messenger, WhatsApp, or Google Hangouts for communicating with you. We will never ask you to send us money, technology, or anything else to work for our company. If you believe you are the victim of a scam, please review your local government consumer protections guidance and reach out to them directly.
Senior Developer employer: Critical Mass
At Critical Mass, we pride ourselves on being an exceptional employer that fosters a collaborative and innovative work culture. Our commitment to employee growth is evident through our internal learning programs and mentorship opportunities, ensuring that you can thrive in your role as a Senior Developer. With competitive benefits, early dismissal Fridays, and a focus on work-life balance, we create an environment where you can excel both personally and professionally.
StudySmarter Expert Advice🤫
We think this is how you could land Senior Developer
✨Tip Number 1
Network like a pro! Reach out to your connections in the industry, attend meetups, and engage in online communities. You never know who might have the inside scoop on job openings or can refer you directly.
✨Tip Number 2
Nail that interview prep! Research the company, understand their tech stack, and be ready to discuss how your experience aligns with their needs. Practise common coding challenges and be prepared to showcase your problem-solving skills.
✨Tip Number 3
Show off your projects! Create a portfolio that highlights your best work, especially those that demonstrate your front-end skills. Make sure it’s easy to navigate and visually appealing – just like the web apps you’ll be building!
✨Tip Number 4
Don’t forget to follow up! After an interview, send a quick thank-you email to express your appreciation for the opportunity. It keeps you fresh in their minds and shows your enthusiasm for the role.
We think you need these skills to ace Senior Developer
Some tips for your application 🫡
Tailor Your Application:Make sure to customise your CV and cover letter for the Senior Developer role. Highlight your experience with HTML, CSS, and JavaScript, and mention any relevant projects that showcase your skills in front-end development.
Show Off Your Code Quality:Since we value code quality, include examples of your work that demonstrate your ability to write clean, maintainable code. If you have a GitHub profile or portfolio, link it in your application to give us a peek at your coding style.
Be Clear and Concise:When writing your application, keep it straightforward. Use clear language and avoid jargon unless it's relevant to the role. We want to see your personality shine through, so don’t be afraid to let us know what makes you tick!
Apply Through Our Website:We encourage you to apply directly through our website. It’s the best way to ensure your application gets into the right hands. Plus, it shows us you’re keen on joining our team!
How to prepare for a job interview at Critical Mass
✨Know Your Tech Stack
Make sure you’re well-versed in HTML, CSS, and JavaScript (ES6+). Brush up on your knowledge of responsive design and front-end architectures. Be ready to discuss how you've applied these skills in past projects.
✨Showcase Your Problem-Solving Skills
Prepare examples of how you've debugged complex front-end issues or improved performance. Highlight your experience with code reviews and mentoring others, as this aligns with the collaborative culture they value.
✨Understand Their Workflow
Familiarise yourself with Git and modern collaborative workflows. Be prepared to discuss your experience with pull requests and branching strategies, as well as how you maintain coding standards in your work.
✨Ask Insightful Questions
Prepare thoughtful questions about their development processes, team dynamics, and how they approach new technologies. This shows your genuine interest in contributing to their team and helps you gauge if it’s the right fit for you.
