Learn about using Sentry with Flask.

The Flask integration adds support for the Flask Web Framework.

Install sentry-sdk from PyPI with the flask extra:

pip install --upgrade "sentry-sdk[flask]"

If you have the flask package in your dependencies, the Flask integration will be enabled automatically when you initialize the Sentry SDK.

Configuration should happen as early as possible in your application's lifecycle.

import sentry_sdk

    # Set traces_sample_rate to 1.0 to capture 100%
    # of transactions for tracing.
    # Set profiles_sample_rate to 1.0 to profile 100%
    # of sampled transactions.
    # We recommend adjusting this value in production.

Our Python SDK will install the Flask integration for all of your apps. It hooks into Flask’s signals, not anything on the app object.

from flask import Flask

sentry_sdk.init(...)  # same as above

app = Flask(__name__)

def hello_world():
    1 / 0  # raises an error
    return "<p>Hello, World!</p>"

When you point your browser to http://localhost:5000/ a transaction in the Performance section of sentry.io will be created. Additionally, an error event will be sent to sentry.io and will be connected to the transaction.

It takes a couple of moments for the data to appear in sentry.io.

After initialization:

  • If you use flask-login and set send_default_pii=True in your call to init, user data (current user id, email address, username) will be attached to the event.
  • Request data will be attached to all events: HTTP method, URL, headers, form data, JSON payloads. Sentry excludes raw bodies and multipart file uploads.
  • Logs emitted by app.logger or any logger will be recorded as breadcrumbs by the Logging integration (this integration is enabled by default).

If you add FlaskIntegration explicitly to your sentry_sdk.init() call you can set options for FlaskIntegration to change its behavior:

import sentry_sdk
from sentry_sdk.integrations.flask import FlaskIntegration

    # ...
    integrations = [

You can pass the following keyword arguments to FlaskIntegration():

  • transaction_style:

    def myendpoint():
        return "<p>Hello, World!</p>"

    In the above code, you would set the transaction to:

    • /myurl/<foo> if you set transaction_style="url".
    • myendpoint if you set transaction_style="endpoint"

    The default is "endpoint".

  • Flask: 1.0+
  • Python: 3.6+

The versions above apply for Sentry Python SDK version 2.0+, which drops support for some legacy Python and framework versions. If you're looking to use Sentry with older Python or framework versions, consider using an SDK version from the 1.x major line of releases.

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