LiveDebugger is a browser-based tool for debugging applications written in Phoenix LiveView - an Elixir library designed for building rich, interactive online experiences with server-rendered HTML.
Designed to enhance your development experience LiveDebugger gives you:
- 🌳 A detailed view of your LiveComponents tree
- 🔍 The ability to inspect assigns for LiveViews and LiveComponents
- 🔗 Tracing and filtering of their callback executions
- 🔦 Components highlighting
meet.livedebugger.mp4
Important
LiveDebugger should not be used on production - make sure that the dependency you've added is :dev only
Add live_debugger to your list of dependencies in mix.exs:
defp deps do
[
{:live_debugger, "~> 0.2.0", only: :dev}
]
endFor full experience we recommend adding below line to your application root layout. It attaches meta tag and LiveDebugger scripts in dev environment enabling browser features.
# lib/my_app_web/components/layouts/root.html.heex
<head>
<%= Application.get_env(:live_debugger, :live_debugger_tags) %>
</head>After you start your application, LiveDebugger will be running at a default port http://localhost:4007.
LiveDebugger has Igniter support - an alternative for standard mix installation. It'll automatically add LiveDebugger dependency and modify your root.html.heex after you use the below command.
mix igniter.install live_debuggerSince version v0.2.0 you can install official LiveDebugger DevTools extension, giving you the ability to interact with its features alongside your application's runtime.
- Chrome extension
- Firefox extension - coming soon!
Note
Ensure the main LiveDebugger dependency is added to your mix project, as the browser plugin alone is not enough.
Some features require injecting JS into the debugged application. They are enabled by default, but you can disable them in your config.
# config/dev.exs
# Disables all browser features and does not inject LiveDebugger JS
config :live_debugger, :browser_features?, false
# Disables only debug button
config :live_debugger, :debug_button?, false
# Disables only components highlighting
config :live_debugger, :highlighting?, false
# Used when LiveDebugger's assets are exposed on other address (e.g. when run inside Docker)
config :live_debugger, :external_url, "http://localhost:9007"In router.ex of your Phoenix app, make sure your locally running Phoenix app can access the LiveDebugger JS files on port 4007. To achieve that you may need to extend your CSP in :dev mode:
@csp "{...your CSP} #{if Mix.env() == :dev, do: "http://127.0.0.1:4007"}"
pipeline :browser do
# ...
plug :put_secure_browser_headers, %{"content-security-policy" => @csp}
# config/dev.exs
# Allows you to disable LiveDebugger manually if needed
config :live_debugger, :disabled?, true
# Time in ms after tracing will be initialized. Useful in case multi-nodes envs
config :live_debugger, :tracing_setup_delay, 0
# Used when working with code reloading and traces are not visible.
# WARNING! This may cause some performance issues.
config :live_debugger, :tracing_update_on_code_reload?, true
# LiveDebugger endpoint config
config :live_debugger,
ip: {127, 0, 0, 1}, # IP on which LiveDebugger will be hosted
port: 4007, # Port on which LiveDebugger will be hosted
secret_key_base: "YOUR_SECRET_KEY_BASE", # Secret key used for LiveDebugger.Endpoint
signing_salt: "your_signing_salt", # Signing salt used for LiveDebugger.Endpoint
adapter: Bandit.PhoenixAdapter, # Adapter used in LiveDebugger.Endpoint
server: true, # Forces LiveDebugger to start even if project is not started with the `mix phx.server`For those planning to contribute to this project, you can run a dev version of the debugger with the following commands:
mix setup
iex -S mixIt'll run the application declared in the dev/ directory with the library installed.
LiveReload is working both for .ex files and static files, but if some styles don't show up, try using this command
mix assets.build:devTo learn about our upcoming plans and developments, please visit our discussion page.
LiveDebugger is created by Software Mansion.
Since 2012 Software Mansion is a software agency with experience in building web and mobile apps as well as complex multimedia solutions. We are Core React Native Contributors, Elixir ecosystem experts, and live streaming and broadcasting technologies specialists. We can help you build your next dream product – Hire us.
Copyright 2025, Software Mansion
Licensed under the Apache License, Version 2.0