Senior Software Engineer, Backend

About the role

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.

We’re looking for backend engineers who have experience building and operating reliable, scalable systems. Your background may be in product engineering, infrastructure, platform engineering, or a combination of these. What matters most is strong backend fundamentals, sound systems thinking, and the ability to take ownership of complex technical problems from design through production.

Teams

• Duolingo Score

  Duolingo Score reflects a learner's real language proficiency. As the team lead/backend engineer on this small, high-impact team, you'll help make learners care about their score as much as they care about their streak. You'll partner closely with the Score Pillar's product and design team and our iOS and Android engineers, working on systems that power score calculation, proficiency modeling, and how score surfaces across the app — including integrations with external platforms like LinkedIn.

• Time Spent Learning

  The Time Spent Learning team is dedicated to motivating learners to spend more time engaging meaningfully with the Duolingo app. This small, cross-functional team owns a metric that shapes learning outcomes for millions of users and iterates on mechanics to drive consistent, high-effort practice.

• Ads

  The Monetization pillar builds systems that fund Duolingo’s mission — from subscriptions to advertising. As a Backend Engineer on the Ads team, you'll work on growing and scaling Duolingo's ads business, including ad serving, mediation, demand, and in-product ad formats. You'll collaborate with product, design, data science, machine learning, and ad operations.

• Observability

  The Observability team builds infrastructure and tools that give engineers confidence and clarity at Duolingo scale. You'll create monitoring, alerting, and debugging experiences, build instrumentation frameworks, deploy telemetry infrastructure, design dashboards, and connect signals to catch issues before they impact learners.

Responsibilities

• 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 timely delivery

Requirements

• 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

Preferred Qualifications

• Industry experience building high-traffic APIs using public cloud providers
• Experience with industry observability technology, such as OpenTelemetry, Grafana, Prometheus, or DataDog

Pay

Salary Range: $182,800—$247,300 USD. Base salary is supplemented by equity compensation. The range is subject to change and depends on factors like work experience, skills, and internal peer comparisons.

Benefits

Take a peek at how we care for our employees' holistic well-being with our benefits here.