Senior Developer

The Critical Mass technology team is looking for an inspired, motivated, and experienced Senior Developer to join our Communications team for a contract engagement. We are an experience design agency with a focus on the customer, which means that collaboration and precision execution are at the heart of our process. You'll be working on high-visibility campaign and consumer‑facing websites where pixel‑perfect design execution and responsive optimization are critical to delivering a premium user experience.

This is a contract position from July 1 – September 25, 2026.

• Deliver pixel-perfect front-end implementations that match design comps across all devices and viewport sizes
• Build responsive campaign layouts with modern animation‑rich marketing pages using modern HTML, CSS, and Java Script
• Work on individual components and page sections within robust, complex websites
• Collaborate with Design, UX, and the delivery team to ensure seamless implementation of designs
• Optimize page performance and ensure WCAG accessibility compliance
• Jump into high‑velocity production work with minimal onboarding and deliver under tight timelines
• Take ownership of your work and drive solutions proactively with minimal supervision
• Support the team with clear code, documentation, and knowledge sharing

• 4+ years demonstrated experience using Vanilla Java Script
• 5+ years’ experience using HTML5 semantic markup, CSS3, and CSS/SASS preprocessing
• 5+ years building SVG-based animations and responsive consumer‑facing websites
• Strong expertise in pixel‑perfect design implementation and responsive design across devices
• Full command of Git, the terminal, and modern development fundamentals
• Strong troubleshooting ability and technical analysis skills – including web performance optimization
• Proven ability to jump into projects quickly and deliver quality work under pressure
• Strong communication skills with a self‑sufficient, collaborative approach to teamwork
• Fluency with implementing pre‑made components from a component library such as Material UI or similar
• Proven knowledge using utility classes, grid classes, and utilizing CSS frameworks such as Bootstrap, Foundation, Materialize, or similar
• Experience with navigating Sketch design files to find font and color styles and dimensions
• Proven track record of delivering production‑quality code on high‑visibility projects
• Practice or exposure to developing software with Large Language Models (LLMs), including writing and integrating AI‑assisted code
• Experience with web animations (CSS and JS) and web animation libraries (GSAP)

• Capability with Handlebars or other templating engines
• Skill with Webpack or other front‑end build system optimization tools
• Experience working in an agency or fast‑paced production environment
• Familiarity with design‑to‑development handoff processes and design systems
• Awareness with the Atlassian suite of tools (JIRA, Bitbucket, Confluence)
• WCAG accessibility expertise

$105,000—$115,000 CAD

Critical Mass is an equal opportunity employer.