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. As a Backend Engineer, you will work on building the APIs that power our products and give our learners a best-in-class experience. Our microservices infrastructure is composed of hundreds of endpoints serving hundreds of millions of requests per day. You will partner with your team members on identifying requirements and designing services that are fast, resilient, and cost-effective. You will have ownership over the entire lifecycle of your services and associated infrastructure, and ensure they are always operating well.