django-devbar 0.1.0

Lightweight performance devbar for Django

django-devbar

Lightweight performance devbar for Django. Shows DB query count, query duration, and response time.

Installation

pip install django-devbar

Add to your middleware as early as possible, but after any middleware that encodes the response (e.g., GZipMiddleware):

MIDDLEWARE = [
    "django.middleware.security.SecurityMiddleware",
    "django_devbar.DevBarMiddleware",
    # ...
]

Configuration

# Position: bottom-right, bottom-left, top-right, top-left (default: bottom-right)
DEVBAR_POSITION = "top-left"

# Show HTML overlay (default: DEBUG)
DEVBAR_SHOW_BAR = True

# Add X-DevBar-* response headers (default: False)
DEVBAR_SHOW_HEADERS = True

Response Headers

When DEVBAR_SHOW_HEADERS = True, performance metrics are added as HTTP response headers. This is useful for:

• API endpoints where the HTML overlay can't be displayed
• Automated testing to assert performance thresholds (e.g., fail CI if query count exceeds a limit)
• Monitoring tools that can capture and aggregate header values

Headers included:

Header	Description
X-DevBar-Query-Count	Number of database queries executed
X-DevBar-Query-Duration	Total time spent in database queries (ms)
X-DevBar-Response-Time	Total request-response cycle time (ms)
X-DevBar-Has-Duplicates	Present (value 1) if duplicate queries detected