Senior Frontend Engineer, Ads Formats

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 130 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com . Team Description The Ad Formats team builds and evolves Reddit’s ad experiences across all platforms and all format types, including image, video, carousel, shopping, etc. The team defines how those ads behave across placements like feed, conversation, search, making sure each format works in the right surfaces and contexts across Reddit. The team supports the end-to-end user ad experience, including media rendering, click behavior, special click variants like lead gen, and the UI details that make promoted content feel native to Reddit while optimizing for advertiser's goals. Within this area, the Ad Formats Foundation team owns the common infrastructure behind all ad formats, with a mission to improve developer efficiency, system reliability, and long-term scalability across the stack. We are responsible for modernizing core formats infrastructure, standardized format data, drive cross-platform consistency and compliance for ad formats to reduce bugs and allow the formats team to iterate quickly and improve the developer velocity. Our goal is to continuously improve ad formats infrastructure, with a focus on increasing developer efficiency and system reliability through tech stack modernization, scalability investments, and compliance work. Role Description We’re looking for a senior frontend engineer with deep JavaScript, TypeScript, and browser platform expertise to help strengthen Reddit’s advertising experiences across desktop and mobile web. You will partner with product and design to work through ambiguous requirements and make sound product and engineering tradeoffs. You’ll work closely with Ads and Web Platform engineers to solve complex frontend challenges while maintaining site performance, accessibility, and a dependable user experience. This role is a strong fit for someone who enjoys browser-level problem solving, navigating ambiguity, and building maintainable systems with measurable impact. Responsibilities • Develop resilient frontend approaches to reduce ad disruptions, drawing on deep knowledge of JavaScript, TypeScript, HTML, CSS, the DOM, and browser networking. • Partner with Ads and Web Platform teams to integrate solutions into shared rendering infrastructure, frontend architecture, and build systems. • Design controlled experiments and phased rollouts to measure effectiveness while protecting site performance, accessibility, and user experience. • Build instrumentation and monitoring to track mitigation effectiveness, detect regressions, and guide iteration. • Implement ad rendering, event collection, click handling, browser extensions across multiple Ad formats. • Contribute to broader foundational improvements in web advertising reliability, performance, and measurement. • Raise engineering quality through thoughtful technical design, testing, code reviews, documentation, and mentorship. Required Qualifications • 5+ years of experience building production web applications with JavaScript, TypeScript, and/or React. • Comfort using Codex, Cursor, Claude, or comparable agentic coding tools in day-to-day software development. • A track record of independently delivering complex frontend projects from technical design through launch and iteration. • Sound judgment in frontend architecture, state management, component design, testing, and API