Python

Install

pip install retrace-kit

Optional framework extras: pip install retrace-kit[fastapi] or pip install retrace-kit[django].

PyPI: retrace-kit. Source: sdk-python. Announcement: Python error tracking.

Initialize

import os

from retrace_kit import init

init(api_key=os.environ["RETRACE_KIT_API_KEY"])

api_key is enough. Optional release should come from importlib.metadata.version — see SDK → Release.

Option	Default	Notes
api_key	-	Required. Blank key disables sending and logs a warning.
environment	-	Attached to every event (for example production).
enabled	True	Set False to keep hooks quiet locally.

Auto-capture

After init, the SDK installs handlers for uncaught exceptions, threading errors, and asyncio loop exceptions. Events include userAgent like Python/3.12.0 and tag runtime:python.

Identical crashes inside a 30-second window are deduplicated client-side. init also sends a session ping. Handled errors: capture via capture_exception.

FastAPI

import os

from fastapi import FastAPI

from retrace_kit import init
from retrace_kit.integrations.fastapi import setup_fastapi

init(api_key=os.environ["RETRACE_KIT_API_KEY"])
app = FastAPI()
setup_fastapi(app)

Unhandled 5xx and uncaught exceptions become events with route breadcrumbs and the request URL. Client errors such as HTTPException(404) are not reported.

Django

Add middleware in settings.py:

MIDDLEWARE = [
    # ...
    "retrace_kit.integrations.django.RetraceKitMiddleware",
]

Call init in settings.py or wsgi.py. Unhandled view exceptions become events; Http404 and PermissionDenied are ignored.

Manual capture

from retrace_kit import add_breadcrumb, capture_exception, set_tag, set_user

set_user({"id": "user_123"})
set_tag("plan", "pro")
add_breadcrumb(type="common", name="checkout", value="started")

try:
    checkout()
except Exception as error:
    capture_exception(error, context={"url": str(request.url)})

FastAPI and Django integrations attach the request URL for you. Elsewhere, pass url in context so the issue page has a route.

See also breadcrumbs, current user, incidents.

Notes

• Python 3.10+ — typed public API with mypy coverage.
• Zero core deps — framework extras are optional.
• Request URL — FastAPI/Django set it; otherwise pass url to capture_exception.

Examples live in the sdk-python repo (examples/).