How Duolingo Saves 500+ Hours Monthly and $1.1M Yearly with Glean

Duolingo is the world’s most downloaded language learning application, with hundreds of millions of users learning languages through its gamified platform. As Duolingo scaled its engineering and business teams, internal knowledge became increasingly difficult to navigate. Information lived across Google Drive, Slack, Confluence, Zendesk, and other tools — each requiring separate searches, separate contexts, and separate mental models for where to look first.

To address this, Duolingo built an internal search tool called Metasearch. But without advanced filtering or relevance ranking, Metasearch delivered slow and unreliable results. Employees still spent significant time hunting for documents, asking colleagues for help, or redoing work that already existed somewhere in the organization. As the company grew, these friction costs compounded — duplicated efforts, slower onboarding, and lost focus from high-impact work.

Duolingo deployed Glean to connect and index its full tool stack, making information instantly searchable across the company. Glean Chat added a conversational layer: instead of sending Slack messages and waiting for responses, employees could ask Glean directly and receive clear, contextual answers drawn from company knowledge. For Art Chaidarun, a Principal Software Engineer at Duolingo, Glean Chat represented a shift in how people seek information at work — similar in pattern to the shift from traditional search to conversational AI, but grounded in company-specific knowledge.

The impact was tangible and measurable. Duolingo teams now save more than 500 hours every month that would otherwise go to searching for information or recreating existing work. Across a year, those savings exceed $1.1 million in recovered time, delivering a 5x return on the company’s investment in Glean. Employees can find martech evaluations, onboarding materials, and due diligence reports instantly — from Slack, a browser extension, or any device — without interrupting their workflow to ask a colleague.

For Duolingo, the value of accessible knowledge is not just operational efficiency but mission alignment. Every hour an engineer or business analyst does not spend searching for information is an hour available for building the features and experiences that help people learn languages. Glean has become part of how Duolingo scales its team without scaling its internal friction.