Sr. Optimizely Developer

Horizontal Talent; Philadelphia (Philadelphia County); On-site; USD 79,000 - 130,000; Full time

Benefits offered by this job

Medical insurance

Dental insurance

Vision insurance

Retirement plan

Job summary

Horizontal Talent seeks a Senior Optimizely Developer to build scalable CMS solutions, run sophisticated experiments, and leverage AI-assisted tools to accelerate development. The role focuses on integrating Optimizely with enterprise platforms, designing robust CMS architectures, and delivering high-quality digital experiences for B2B audiences.

You will collaborate with CRO, product, and design teams to prototype solutions and translate designs into polished experiences using advanced testing

Qualifications

• 5+ years of full-stack web development experience.
• 3+ years in Optimizely ecosystem.
• Strong backend development with C# and .NET Core/MVC in Optimizely CMS.
• Advanced frontend experience with HTML5, CSS3/SASS, and JavaScript (Vanilla, ES6+, React, or Vue).
• Deep understanding of Optimizely concepts: Project JS, visual tags, audiences, anti-flicker, caching.
• Experience building for complex B2B sites, lead gen, gated content workflows.
• Strong Git knowledge and CI/CD familiarity (Azure DevOps or GitHub Actions).
• Independent worker who collaborates well with CRO, product, and design teams.

Responsibilities

• Build and maintain reusable components, templates, and content models in Optimizely CMS.
• Design scalable CMS architecture with performance and Core Web Vitals in mind.
• Develop integrations between Optimizely CMS and Salesforce, Marketo, Adobe Commerce, and internal systems.
• Create advanced A/B, split, and multivariate tests in Optimizely Web Experimentation.
• Implement personalized web experiences for targeted B2B audiences and ABM campaigns.
• Collaborate on server-side testing and feature flagging when frontend testing isn’t ideal.
• Perform cross-browser and cross-device testing to ensure stable UX.
• Define and document best practices and governance for Optimizely work.
• Work with CRO, product, and design to translate wireframes into live experiences.
• Leverage AI-assisted tools to speed up coding, debugging, testing, and experiments.

Skills

Full-stack development

Optimizely CMS

C# / .NET

HTML CSS JS

Project JS

Git CI/CD

Cross-functional teamwork

AI tools

Tools

Azure DevOps

GitHub Actions

Salesforce

Marketo

Job description

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.

• For those that join the team, we offer competitive compensation and benefits including medical, dental, vision, and retirement.

The pay range for this role is $79,000 - $130,000 per year based on qualifications and experience.