Software Engineer II, Backend

Our mission at Duolingo is to develop the best education in the world and make it universally available. It’s a big mission, and that’s where you come in! At Duolingo, you’ll join a team that cares about finding innovative solutions to complex technical problems , running countless experiments (300+ at a time!) with our massive user base to make data-driven decisions, and educating our users and employees alike. You’ll have limitless learning opportunities, mentorship and collaboration with world-class minds, and a variety of projects with large scopes — while doing work that’s both fun and meaningful. Join our life-changing mission to develop education for our half a billion (and growing!) learners around the world. Below you can find more information about the team we're hiring for: Content Infrastructure: As a backend engineer on the Content Infrastructure Team, you'll build features that make up the core backbone of the learning experience on Duolingo. Our short-form lessons are where learners spend the majority of their time on the app, and our team's mission is to build and update infrastructure to enable quick iteration and improve content quality in these sessions. You'll work on scaling new exercise types that support our learners in practicing speaking or grammar in bite-sized formats, as well as re-architecting our infrastructure in other ways to help set our teams up for success in the future. We're looking for engineers who are passionate about designing scalable systems to help improve the quality of our short-form sessions! Ads: Duolingo's Monetization pillar builds the systems that fund our mission — from subscription packaging and advertising to ML-powered personalization. As a Senior iOS Engineer on the Ads team, you'll work on a product engineering team responsible for growing and scaling Duolingo's ads business: high-quality ads that delight learners, fit seamlessly into the product experience, and meaningfully contribute to our bottom line. The