Join a fast-moving digital marketing team that is investing heavily in modern web technology, experimentation, and data-driven growth. This Senior Optimizely Developer role is a great fit for someone who enjoys building scalable CMS solutions, launching sophisticated experiments, and using AI-assisted tools to work faster and smarter.

Responsibilities

• Build and maintain reusable components, page templates, and content models within Optimizely CMS to help marketing teams launch web pages efficiently.
• Design CMS architecture that supports scalability, security, and strong performance, including Core Web Vitals optimization.
• Develop and support integrations between Optimizely CMS and enterprise platforms such as Salesforce, Marketo, Adobe Commerce, and internal systems.
• Create and deploy advanced A/B, split, and multivariate tests in Optimizely Web Experimentation, including custom DOM manipulation and dynamic content changes.
• Implement personalized web experiences for targeted B2B audiences and account-based marketing campaigns.
• Partner on server-side testing and feature flagging when frontend testing is not the best fit.
• Perform thorough cross-browser and cross-device testing to help ensure smooth, consistent user experiences with minimal flicker or layout shift.
• Define and document best practices, technical standards, and governance guidelines for Optimizely-related work.
• Collaborate closely with CRO, product, and design teams to evaluate ideas, prototype solutions, and translate designs into polished digital experiences.
• Use AI-assisted development tools to accelerate coding, debugging, testing, and experimentation workflows.

Skills

• 5+ years of full-stack web development experience.
• At least 3+ years of hands-on experience working within the Optimizely ecosystem.
• Strong backend development skills with C# and .NET Core/MVC, especially in Optimizely CMS environments.
• Advanced frontend experience with HTML5, CSS3/SASS, and JavaScript, including Vanilla JS, ES6+, jQuery, React, or Vue.
• Deep understanding of Optimizely platform concepts such as Project JS, visual tags, audience targeting, anti-flicker approaches, and caching behavior.
• Experience building for complex B2B websites, including lead generation and gated content workflows.
• Strong Git knowledge and familiarity with modern CI/CD workflows such as Azure DevOps or GitHub Actions.
• Ability to work independently while also partnering effectively with cross-functional teams.
• A proactive, solution-oriented mindset with a focus on speed, quality, and continuous improvement.

Preferred Skills

• Active Optimizely Developer certification in CMS or Web Experimentation.
• Experience supporting server-side experimentation and feature flagging initiatives.
• Familiarity with UX/UI collaboration and translating wireframes or Figma designs into interactive experiences.
• Comfort using AI tools such as GitHub Copilot or ChatGPT to support development efficiency.
• Experience working in remote-first environments and collaborating across multiple locations.

Horizontal is committed to fostering an inclusive environment where all qualified candidates can thrive. We value diversity, equity, and inclusion as essential to building strong teams, better ideas, and better outcomes.