Lead Developer SaaS

We’re looking for a Lead Developer who lives at the intersection of JavaScript engineering and conversion optimization. You won’t just write code - you’ll own the technical architecture of a product whose entire purpose is making pages convert better. That means you need to care as much about DOM manipulation and page speed as you do about CRO principles, GTM strategy, and what makes a visitor click.

This is a hands-on leadership role. You’ll write code daily, make architectural decisions, and set the technical direction for the product - while mentoring a small team of developers as we scale.

What You’ll Do

• Own the core JavaScript injection engine - the script that loads on client sites, modifies the DOM, renders custom landing page elements, and does it all without degrading site performance
• Architect and build the page editor / builder interface that non-technical users interact with to create and customize landing pages
• Design the A/B testing and experimentation framework - traffic splitting, variant rendering, goal tracking, and statistical reporting
• Integrate with analytics platforms (GA4, GTM, Segment, Meta Pixel, etc.) to ensure conversion events fire correctly across all page variants
• Optimize for Core Web Vitals - every millisecond of load time you add is revenue lost; you’ll obsess over script weight, async loading, render-blocking, and CLS impact
• Build personalization logic - dynamic content based on UTM parameters, referral source, device, geo, return visitor status, and custom audience segments
• Collaborate directly with growth and marketing teams to understand what they need to test and ship, then build the tooling that lets them move without filing engineering tickets
• Establish code quality standards, testing practices, and deployment pipelines for the engineering team

Do you have experience in TypeScript?, * 5+ years of professional JavaScript/TypeScript development, with deep experience in frontend frameworks (React, Vue, or Svelte)

• Hands-on experience building or working on tools that inject scripts into third-party sites (tag managers, A/B testing platforms, personalization engines, browser extensions, or similar)
• Strong understanding of the DOM, Shadow DOM, MutationObservers, and client-side rendering - you know how to manipulate a page you don’t control without breaking it
• Real experience with CRO and landing page optimization - you understand conversion funnels, statistical significance, multivariate testing, and what actually moves the needle on a page
• GTM / tag management fluency - you’ve configured complex GTM setups, custom event tracking, data layers, and cross-domain tracking
• Performance engineering mindset - you’ve profiled, optimized, and debugged frontend performance issues in production at scale
• Experience with at least one backend language/framework (Node.js, Python/Django, or similar) for API and data layer work, * Prior experience at a CRO, experimentation, or landing page platform (Optimizely, VWO, Unbounce, Mutiny, Instapage, Convert, or similar)
• Experience with e-commerce platforms and their frontend architectures (Shopify, BigCommerce, custom headless setups)
• Familiarity with CDN architecture, edge computing, and how to serve injected scripts with minimal latency globally
• Understanding of SEO implications of client-side rendering and JavaScript-injected content (cloaking risks, Googlebot rendering, etc.)
• Experience leading or mentoring a small engineering team (2-5 developers)

$49,985.98 - $110,000.00 a year - Full-time, Contract, Pulled from the full job description

• Flexible schedule, What You’ll Get
• Ground-floor technical leadership of a product with live, paying customers and a clear growth trajectory
• Direct impact on revenue - every feature you build is measurable in conversion lift
• Autonomy to make architectural decisions and shape the product’s technical future
• Competitive salary + equity
• In-person collaboration with a small, senior team that ships fast, * Flexible schedule