plotly / dash

GitHub

Code

How plotly/dash is laid out, and where to start for common changes.

There is no import map for this report yet.

Where to start reading

Repository root
Repository root
Likely public API
Likely public API
Likely start-up file
Suggested starting pointAI
Suggested starting pointAI
Suggested starting pointAI

Find files for a task

Add a New Callback

Use the @app.callback() decorator to bind component properties to Python functions
The callback system automatically serializes/deserializes JSON payloads via websocket

Add a New Component Type

Run component generation to auto-create Python wrapper classes
Generated class inherits from base_component.Component and registers props/callbacks

Add a Multi-Page Application

Register pages using @page decorator or register_page() call
Use dcc.Location component to capture current pathname and conditionally render layouts

Configure Persistent Storage

Choose storage backend: Redis, diskcache, or local memory in _shared_storage/
Pass storage instance to dcc.Store or use dcc.Store with persistence=True flag
Storage layer automatically syncs data across browser tabs via websocket polling

Change the public API

Trace runtime behavior

Add or update tests

Change build or automation

RepoPilot lists up to 500 files, so a file missing here may still exist.

Files marked “likely” are guessed from their names.

Code quality and hotspots

Largest source files

Branch points78 per file on average
Code issues0 errors, 20 warnings
Largest file3,009 lines
Hotspot load9 high-risk files

Static checks on the 15 largest source files.

Tests, CI and tooling

CIGitHub Actions5 workflows
Tests505 test filesJest/Vitest · Pytest · 0.86 test files per source file (file count, not coverage)
Dependency updatesNo config detected

Test folders: components/dash-core-components/tests/integration/dropdown · components/dash-core-components/tests/integration/calendar · components/dash-core-components/tests/integration/graph

Hotspots

dash/dash.py40 commits in 180 days · 99 branch points
dash/_callback.py33 commits in 180 days · 34 branch points
dash/backends/_fastapi.py37 commits in 180 days · 35 branch points
dash/backends/ws.py19 commits in 180 days · 32 branch points
dash/backends/_quart.py27 commits in 180 days · 19 branch points
dash/dash-renderer/src/actions/callbacks.ts14 commits in 180 days · 196 branch points
dash/dash-renderer/src/actions/dependencies.js11 commits in 180 days · 273 branch points
dash/_stream_hub.py12 commits in 180 days · 25 branch points

Files that change often and branch heavily, highest first. Branch points count if, loop, case, catch, ternary, && and || in the file.