Duolingo boosts developer speed up to 25% with GitHub Copilot and Codespaces
Duolingo's developers needed to be as efficient as possible, but fragmented tooling across repositories—including third-party tools like Gerrit and PullApprove—created inconsistent workflows and prevented developers from moving easily between projects.
How it works
Common implementation structure
How this type of workflow is generally built, generalized across documented cases — not tied to any one vendor's stack. Click any stage to read what happens there. Specific products that implement these stages appear in “Tools commonly seen” below.
Stage 1 · Developer initiates coding task
A developer begins writing code or writes natural language comments describing what they want the code to do.
GitHub Copilot increased developer speed by at least 25% for those new to a codebase and 10% for familiar ones; a custom Slack integration cut code review turnaround from three hours to one; and Codespaces reduced the largest repo setup time from hours or days to one minute.
What failed first
Relying on third-party tools like Gerrit and PullApprove for code review left Duolingo's primary repositories with widely varying cultures and pull request processes, creating inefficiency and preventing developers from moving easily between repos.