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: 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 team owns ad serving, mediation and demand, in-product ad formats and surfaces, and more. You'll work cross-functionally with product, design, data science, machine learning, and ad operations. 🧠 You will... Collaborate on software projects with product design and backend aspects Develop, release, and maintain backend services and/or infrastructure Lead individual project priorities, milestones, and ensure we're always shipping ✅ You have... A Bachelor’s degree in Computer Science or a related technical field Strong competencies in data structures, algorithms, and software design Experience programming in Java, Python, or Kotlin Solid understanding of one or more database technologies ⭐ Exceptional candidates will have... Industry experience building high-tr