Codex
Connectome Data Explorer
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 is Sign-In Required? Codex is used by a wide audience, 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, enables 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.
datasets
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FAFB (v783)
Female Adult Fly Brain
139,255 neurons
3,732,460 connections -
BANC (v626)
Female Adult Fly Brain and Nerve Cord
115,151 neurons
2,676,592 connections -
MANC (v1.2.1)
Male Adult Fly Nerve Cord
23,665 neurons
5,305,638 connections -
MAOL (v1.1)
Male Adult Fly Right Optic Lobe
52,445 neurons
6,484,936 connections -
MCNS (v0.9)
Male Adult Fly CNS
166,694 neurons
6,239,112 connections
apps
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Search
Find neurons using free-form or structured queries
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Stats
See statistics and charts for various attributes of all or subset of neurons in the dataset
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Annotations
Browse cell types, labels, and groupings of the neurons in the dataset
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Cell Details
Information about individual cells, their connectivity, similar/twin cells, 3D rendering and annotations
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Neuropils
Visualize and query connections in specific brain regions
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3D Viewer
Visualize queried neurons and synapses in annotated Neuroglancer scenes
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Network Graphs
Visualize connectivity of neurons and their synaptic links
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Pathways
Analyse shortest-paths between pairs of neurons
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Download Data
Export raw data for analysis with other tools / programs
