Senior Developer (Front End)

Role Overview

Senior Developer (Front End) for Critical Mass’ Communications team on a contract engagement.

Key Responsibilities

• Deliver pixel-perfect front-end implementations matching design comps across devices and viewport sizes.
• Build responsive campaign layouts and animation-rich marketing pages using modern web standards.
• Work on individual components and page sections within robust, complex websites.
• Collaborate with Design, UX, and delivery teams to ensure implementations match designs.
• Optimize page performance and ensure WCAG accessibility compliance.
• Join high-velocity production work with minimal onboarding and deliver under tight timelines.
• Take ownership of work; proactively drive solutions with minimal supervision.
• Provide clear code, documentation, and knowledge sharing to support the team.

Required Qualifications

• 4+ years experience with Vanilla JavaScript.
• 5+ years with 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.
• Strong command of Git and modern development fundamentals (including terminal usage).
• Strong troubleshooting and web performance optimization skills.
• Proven ability to ramp quickly and deliver quality work under pressure.
• Strong communication with a self-sufficient, collaborative approach.
• Experience implementing pre-made components from a component library (e.g., Material UI or similar).
• Proven knowledge using utility/grid classes and CSS frameworks such as Bootstrap, Foundation, Materialize, or similar.
• Ability to navigate Sketch design files to extract font/color styles and dimensions.
• Track record of production-quality code on high-visibility projects.
• Exposure to LLM-assisted development, including writing and integrating AI-assisted code.
• Experience with web animations using CSS/JavaScript and GSAP (or similar libraries).

Bonus / Nice to Have

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

Contract Details

• Contract engagement July 1 – July 31, 2026.

Location

• Cupertino, CA.