Senior Engineer - Growth Marketing

Headquarters: United States, California URL: https://buffer.com/ About the role We're looking for a Senior Frontend Engineer to join our Growth Marketing team. This is a hands-on engineering role building the web experiences and systems that help Buffer grow. The work spans building features and pages across buffer.com - interactive tools, benchmarks, referral systems, conversion flows - along with the technical implementation behind them: integrations with marketing tools, analytics and tracking systems, SEO implementations, and backend logic that powers our marketing features. We need someone who's comfortable across the full frontend scope - strong with React and modern web development, but also capable of diving into backend logic, connecting third-party APIs, debugging tracking pipelines, and figuring out what they don't know. You'll collaborate closely with Simon (Director of Marketing), David (Senior Design Engineer), and Kate (Senior Designer). The team values pace and iteration — we ship quickly, learn from real usage, and improve as we go. But we also care about craft — noticing the UX details and maintaining standards while keeping momentum. What you’ll do Lead growth engineering projects, like implementing a localization framework to support international audiences, building referral program logic and attribution systems, rebuilding our tracking implementation to improve accuracy and reliability. You’ll own projects from concept to launch, working closely with marketing, design, and other engineers. Build features on Buffer's marketing site — ship landing pages, interactive tools, and conversion flows that help people discover and try Buffer. Create benchmarks, calculators, and utility content that educate users and drive engagement. Shape marketing platform capabilities by building systems and frameworks that let the team move faster. Create A/B testing infrastructure, develop programmatic page generation for SEO/AEO, implement content management patterns, and build reusable components that make future projects easier to ship. Drive experimentation and optimization — implement A/B tests, optimize conversion funnels, and help the team learn faster through code. Set up experiments, validate results, and iterate based on what we learn. Balance moving quickly with maintaining quality. Improve foundations by maintaining integrations with our marketing technology stack (Segment, GTM, Mixpanel, BigQuery), upgrading dependencies, optimizing performance, and ensuring accessibility. You'll also participate in our on-call rotation and contribute to ongoing system health — fixing bugs, addressing security vulnerabilities, and other improvements that keep buffer.com running smoothly. Contribute to shaping engineering culture by pairing with other engineers, reviewing code, sharing knowledge about growth systems and marketing engineering patterns, and helping level up how we approach frontend work at Buffer. Helpful skills and experience You have strong frontend foundations — solid experience with React, TypeScript, and modern web development. Our site runs on Next.js, but we value adaptability and curiosity over specific stack experience. You're comfortable working across the stack when needed — writing backend logic, building API routes, getting data from various external systems, and connecting third-party integrations together. You've worked with marketing or growth teams and are comfortable with SEO, analytics, A/B testing, and conversion optimization. You've likely built referral systems, programmatic pages, or conversion funnels, and you know how to set up tracking, validate implementations, and measure impact accurately. You're comfortable navigating ambiguity and thinking in systems — you bring clarity and ask good questions to move ideas forward even when requirements aren't fully defined. You look at the full system, understanding how different technologies and goals connect, and build things that can scale and impro