This extension adds a toolbar overlay to Flask applications containing useful information for debugging.



Installing is simple with pip:

$ pip install flask-debugtoolbar


Setting up the debug toolbar is simple:

from flask import Flask
from flask_debugtoolbar import DebugToolbarExtension

app = Flask(__name__)

# the toolbar is only enabled in debug mode:
app.debug = True

# set a 'SECRET_KEY' to enable the Flask session cookies
app.config['SECRET_KEY'] = '<replace with a secret key>'

toolbar = DebugToolbarExtension(app)

The toolbar will automatically be injected into HTML responses when debug mode is on. In production, setting app.debug = False will disable the toolbar.

This extension also supports the Flask app factory pattern by separately creating the toolbar and later initializing it for an app:

toolbar = DebugToolbarExtension()
# Then later on.
app = create_app('the-config.cfg')


The toolbar support several configuration options:

Name Description Default
DEBUG_TB_ENABLED Enable the toolbar? app.debug
DEBUG_TB_HOSTS Whitelist of hosts to display toolbar any host
DEBUG_TB_INTERCEPT_REDIRECTS Should intercept redirects? True
DEBUG_TB_PANELS List of module/class names of panels enable all built-in panels
DEBUG_TB_PROFILER_ENABLED Enable the profiler on all requests False, user-enabled
DEBUG_TB_TEMPLATE_EDITOR_ENABLED Enable the template editor False

To change one of the config options, set it in the Flask app’s config like:



Fork us on GitHub


This was based on the original django-debug-toolbar. Thanks to Michael van Tellingen for the original development of this Flask extension, and to all the individual contributors.

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