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Django Debug Toolbar Panel Fix

DodaTech Updated 2026-06-24 2 min read

In this tutorial, you'll learn about Django Debug Toolbar Panel Fix. We cover key concepts, practical examples, and best practices.

The Problem

Django Debug Toolbar's default panels cover SQL, cache, signals, and templates. When you need to debug custom metrics — like API call counts or custom cache hits — you can add your own panel.

Quick Fix

Wrong — only default panels

# settings.py
DEBUG_TOOLBAR_CONFIG = {}

Output: Only default panels show. No insight into custom performance metrics or application-specific data.

Correct — adding default + custom panels

# settings.py
INSTALLED_APPS = [
    'debug_toolbar',
    ...
]

MIDDLEWARE = [
    'debug_toolbar.middleware.DebugToolbarMiddleware',
    ...
]

INTERNAL_IPS = ['127.0.0.1']

DEBUG_TOOLBAR_PANELS = [
    'debug_toolbar.panels.history.HistoryPanel',
    'debug_toolbar.panels.timer.TimerPanel',
    'debug_toolbar.panels.settings.SettingsPanel',
    'debug_toolbar.panels.headers.HeadersPanel',
    'debug_toolbar.panels.request.RequestPanel',
    'debug_toolbar.panels.sql.SQLPanel',
    'debug_toolbar.panels.staticfiles.StaticFilesPanel',
    'debug_toolbar.panels.templates.TemplatesPanel',
    'debug_toolbar.panels.cache.CachePanel',
    'debug_toolbar.panels.signals.SignalsPanel',
    'debug_toolbar.panels.logging.LoggingPanel',
    'debug_toolbar.panels.redirects.RedirectsPanel',
]

Creating a custom panel

from debug_toolbar.panels import Panel
from django.utils.translation import gettext_lazy as _

class APICallPanel(Panel):
    title = _('API Calls')
    template = 'debug_toolbar/panels/api_calls.html'
    nav_title = _('API')

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.calls = []

    @property
    def nav_subtitle(self):
        return f'{len(self.calls)} calls'

    def process_request(self, request):
        # Hook into your API client to record calls
        pass

    def generate_stats(self, request, response):
        self.record_stats({
            'calls': self.calls,
            'total_time': sum(c['duration'] for c in self.calls),
        })

Registering the custom panel

DEBUG_TOOLBAR_PANELS = [
    ...
    'myapp.panels.APICallPanel',
]

Prevention

  • Add debug_toolbar to installed apps and middleware early.
  • Custom panels let you monitor anything: Celery tasks, external API calls, custom caching.
  • Use Process_request to capture data at request start and generate_stats at response.

Common Mistakes with debug toolbar panel

  1. Non-exhaustive pattern matches that compile with warnings then crash at runtime
  2. Misunderstanding that String is [Char] with poor performance for large text operations
  3. Using foldl instead of foldl' causing stack overflow on large lists

These mistakes appear frequently in real-world DJANGO code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

### How do I show debug toolbar for non-localhost requests?

Set DEBUG_TOOLBAR_CONFIG = {'SHOW_TOOLBAR_CALLBACK': lambda r: True} to show it on all requests (development only).

Can I reorder panels?

Yes. The DEBUG_TOOLBAR_PANELS list determines display order from top to bottom.

Does debug toolbar affect performance?

Slightly — it adds middleware overhead and stores request data. Only enable it in development or staging.

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