Yahoo Mail is the ultimate consumer inbox with hundreds of millions of users. It’s the best way to access your email and stay organized from a computer, phone or tablet. With its beautiful design and lightning fast speed, Yahoo Mail makes reading, organizing, and sending emails easier than ever. About Core Mail We build, enhance, and maintain one of the highest scaling email platforms on the planet. We are the first component in the mail back end, a middle tier, that contains the APIs and business logic through which virtually all mail operations flow. We implement REST APIs for our world-class mail clients (mobile, web, Yahoo, AOL, etc), standards-based protocols (IMAP, POP, etc) for generic mail clients, and industry leading back-end mail synchronization. We own the data platform in metadata, storage, and indexing. And we build even more supporting systems that are part of or support our array of serving and data components. We share about 20 components implemented in 4M lines of code. We directly impact approximately 220 Million users every month, serving billions of requests a day across servers & cloud solutions across the world, and are critical to Yahoo’s success. Our logged-in experience offers even greater value to the rest of Yahoo for serving highly customized experiences. We achieve high scale on each server using async technologies developed in house as well as from open source and cloud technologies. We take an industry leading number of connections, in the order of 100s of thousands on a single server or instance to achieve a very cost friendly footprint. We have a unique opportunity to do hard, challenging work, solving problems at a rare scale, innovating to meet our product & users future needs, & continually modernizing, while sustaining an essential service to users’ daily lives. This is a business critical & central platform to serve all Mail users at the center of Yahoo’s core user base & revenue. Come join this amazing team of engineers to have a more direct impact on serving users and data at uniquely high scale, work on the next generation tech stack, and support innovative product experiences to grow users.