Job Specifications
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.
Our new hires & employees are the future of our organization, and we want to set you up for long-term success. In an effort to do so, we expect our team to work from an office a minimum of 3 days a week.
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.
Critical Mass uses artificial intelligence in our recruitment process to enhance job postings, filter keywords during the review of prospective candidates, and, in some cases, transcribe interviews with our recruiters. Human review remains central to the process, and all hiring decisions are ultimately made by our team.
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.
If U.S. based: https://www.consumer.ftc.gov/articles/j
About the Company
Critical Mass is a team of 1,800 inspired folks based in 12 offices around the world, providing full-service digital capabilities for the greatest brands on Earth. Our secret sauce is our uncompromising design standards, our relentless focus on customers, and an ability to put powerful new technologies to work for our clients.
We work with the best—Apple, Nike, Mars Wrigley, Nissan, Diageo, Airbnb, BMW, BNY Mellon, Johnson & Johnson, and many more—brands who strive for connected digital ecosystems and unparalleled experien...
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