Codex

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Web-based apps for exploring and analyzing large-scale connectomes without installs or massive dataset downloads.
FlyWire and Codex are hosted by the Princeton Neuroscience Institute of Princeton University.
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Why Sign In Required? Codex is used by a wide range of people—from scientists to high school programs—and as of early 2025, over 50,000 users have signed in. To keep Codex free, fast, and available to everyone, access to its apps requires signing in with a Google account. This helps prevent abuse, allows rate-limiting of excessive usage, and reduces server load from automated or malicious activity.

Some static pages (linked below) can be viewed without logging in, but any feature that performs computations on our servers requires you to be signed in. If you don’t have a Google account and can’t create one, please contact flywire@princeton.edu.


For general info visit the FlyWire homepage.

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