---
title: "Flask"
description: "Learn how to set up Sentry in your Flask app, capture your first events and traces, and view them in Sentry."
url: https://docs.sentry.io/platforms/python/integrations/flask/
---

# Flask for Python

If you're using stream mode, this page's references to "transaction" should be applied to service spans instead. See [Streamed Spans](https://docs.sentry.io/platforms/python/tracing/streamed-spans.md) for more information.

## [Prerequisites](https://docs.sentry.io/platforms/python/integrations/flask.md#prerequisites)

You need:

* A Sentry [account](https://sentry.io/signup/) and [project](https://docs.sentry.io/product/projects.md)

* Your application up and running

* Flask:

  * `1.1.4+` (SDK <3.0)
  * `2.0.0+` (SDK 3.0+)

* Python:

  * `3.6+` (SDK <3.0)
  * `3.7+` (SDK 3.0+)

## [Install](https://docs.sentry.io/platforms/python/integrations/flask.md#install)

Run the command for your preferred package manager to add the Sentry SDK to your application:

```bash
pip install "sentry-sdk"
```

*Other available variations of the above snippet: uv, poetry*

This guide requires `sentry-sdk` version 2.70.0 or later. If you already have the SDK installed, upgrade it with `pip install --upgrade sentry-sdk`.

## [Configure](https://docs.sentry.io/platforms/python/integrations/flask.md#configure)

**Error Monitoring** starts working as soon as you call `sentry_sdk.init()`. **Logs** and **Application Metrics** need no extra configuration when using `sentry_sdk.logger` and `sentry_sdk.metrics`, and you'll learn how to send them in steps [#3](https://docs.sentry.io/platforms/python/integrations/flask.md#send-logs) and [#4](https://docs.sentry.io/platforms/python/integrations/flask.md#send-application-metrics-). This guide also enables **Tracing** and **Profiling**.

Want to learn more about these features?

* [**Issues**](https://docs.sentry.io/product/issues.md) (always enabled): Sentry's core error monitoring product that automatically reports errors, uncaught exceptions, and crashes. If you have something that looks like an exception, Sentry can capture it.
* [**Tracing**](https://docs.sentry.io/product/tracing.md): Track software performance while seeing the impact of errors across multiple systems. For example, distributed tracing allows you to follow a request from the frontend to the backend and back.
* [**Profiling**](https://docs.sentry.io/product/profiling.md): Gain deeper insight than traditional tracing without custom instrumentation, letting you discover slow-to-execute or resource-intensive functions in your app.
* [**Logs**](https://docs.sentry.io/product/logs.md): Centralize and analyze your application logs to correlate them with errors and performance issues. Search, filter, and visualize log data to understand what's happening in your applications.
* [**Application Metrics**](https://docs.sentry.io/product/metrics.md) (always enabled): Track and analyze custom application metrics, such as response times and database query durations, to understand trends and patterns in your application's performance and behavior over time.

### [Initialize the Sentry SDK](https://docs.sentry.io/platforms/python/integrations/flask.md#initialize-the-sentry-sdk)

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

If you have the `flask` package in your dependencies, the Flask integration will be enabled and installed for all your apps automatically when you initialize the Sentry SDK. The SDK hooks into Flask's signals, not anything on the app object.

Import and initialize the SDK in your app's entry point:

The snippet also turns on:

* Collection of user data, such as the user's IP address: via [`data_collection`](https://docs.sentry.io/platforms/python/configuration/options.md#data_collection)
* Tracing: via [`traces_sample_rate`](https://docs.sentry.io/platforms/python/configuration/options.md#traces_sample_rate)
* Profiling: via [`profile_session_sample_rate`](https://docs.sentry.io/platforms/python/configuration/options.md#profile_session_sample_rate) and [`profile_lifecycle`](https://docs.sentry.io/platforms/python/configuration/options.md#profile_lifecycle)

Don't need a feature? Remove its options from the snippet.

```python
import sentry_sdk

sentry_sdk.init(
    dsn="https://<key>@o<orgId>.ingest.sentry.io/<projectId>",

    # Check https://docs.sentry.io/platforms/python/data-management/data-collected/ to configure what data is collected
    data_collection={
        "user_info": True,
    },

    # Enables Tracing.
    # Set to 1.0 to capture 100% of spans for tracing.
    # We recommend reducing this value in production.
    traces_sample_rate=1.0,

    # Enables Profiling.
    # Set to 1.0 to profile 100% of sessions.
    profile_session_sample_rate=1.0,
    # Profiles are collected while a transaction is active.
    profile_lifecycle="trace",
)
```

To further customize your setup, review the [Options section](https://docs.sentry.io/platforms/python/integrations/flask.md#options) below.

### [Capturing Errors](https://docs.sentry.io/platforms/python/integrations/flask.md#capturing-errors)

Sentry automatically captures errors and reports issues for you. You can also expect the following for your Flask app:

* If you use `flask-login`, and you've either enabled `user_info` in the [`data_collection` option](https://docs.sentry.io/platforms/python/configuration/options.md#data_collection) or set `send_default_pii=True` in your call to `init`, user data (such as current user ID, email address, username) will be attached to error events. `send_default_pii` will be removed in version 3.0 of the SDK.
* 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 any `app.logger` or *any* logger will be recorded by the [Logging](https://docs.sentry.io/platforms/python/integrations/logging.md) integration (this integration is enabled by default).

Are you using uWSGI?

If you're using uWSGI, note that it doesn't support threads by default. This might lead to unexpected behavior when using the Sentry SDK, from features not working properly to uWSGI workers crashing.

To enable threading support in uWSGI, make sure you have both `--enable-threads` and `--py-call-uwsgi-fork-hooks` on.

Note that automatic tracing on file-like responses when `offloading` is configured is disabled (see [here](https://github.com/getsentry/sentry-python/pull/5556) for why). If you wish to enable tracing on these types of responses, you will need to [manually instrument](https://docs.sentry.io/platforms/python/tracing/instrumentation/custom-instrumentation.md) them.

## [Send Logs](https://docs.sentry.io/platforms/python/integrations/flask.md#send-logs)

Use `sentry_sdk.logger` to send structured logs at different levels. You can include searchable attributes with each message.

To capture records from Python's standard-library `logging` module or Loguru, configure `capture_sentry_logs=True` on the corresponding integration. See the [standard logging](https://docs.sentry.io/platforms/python/integrations/logging.md) and [Loguru](https://docs.sentry.io/platforms/python/integrations/loguru.md) integration guides.

See [Set Up Logs](https://docs.sentry.io/platforms/python/logs.md) for all available logging methods and formatting options.

```python
import sentry_sdk

sentry_sdk.logger.info("Order processed {order_id}", order_id="order-123")
sentry_sdk.logger.warning("Rate limit reached", attributes={"endpoint": "/api/orders"})
```

## [Send Application Metrics NEW](https://docs.sentry.io/platforms/python/integrations/flask.md#send-application-metrics-)

Use `sentry_sdk.metrics` to send counters, gauges, and distributions from your app. Metrics are enabled by default after you initialize the SDK.

See [Set Up Metrics](https://docs.sentry.io/platforms/python/metrics.md) for all available metric types and configuration options.

```python
import sentry_sdk

sentry_sdk.metrics.count("checkout.failed", 1)
sentry_sdk.metrics.gauge("active_connections", 42)
sentry_sdk.metrics.distribution("api_latency", 187, unit="millisecond")
```

## [Verify Your Setup](https://docs.sentry.io/platforms/python/integrations/flask.md#verify-your-setup)

Let's test your setup and confirm that data reaches your Sentry project.

Add this route to your Flask app, then request `/sentry-debug`:

```python
@app.route("/sentry-debug")
def trigger_error():
    1 / 0
```

### [View Captured Data in Sentry](https://docs.sentry.io/platforms/python/integrations/flask.md#view-captured-data-in-sentry)

Now, head over to your project on [Sentry.io](https://sentry.io) to view the collected data (it takes a couple of moments for the data to appear).

Need help locating captured data in your Sentry project?

* Open the [**Issues**](https://sentry.io/orgredirect/organizations/:orgslug/issues/) page and select an error from the issues list to view the full details and context of this error. For more details, see the [Issue Details documentation](https://docs.sentry.io/product/issues/issue-details.md).
* Open the [**Traces**](https://sentry.io/orgredirect/organizations/:orgslug/explore/traces/) page and select a trace to reveal more information about each span, its duration, and any errors. For an interactive UI walkthrough, click [here](https://docs.sentry.io/product/sentry-basics/getting-started-tutorial/generate-first-error.md#ui-walkthrough).
* Open the [**Profiles**](https://sentry.io/orgredirect/organizations/:orgslug/profiling/) page to see your slowest functions and an aggregate flame graph of your most frequent code paths. If tracing is enabled, select a transaction to see the flame graph for that part of your app. For more information, click [here](https://docs.sentry.io/product/profiling/profile-details.md).
* Open the [**Logs**](https://sentry.io/orgredirect/organizations/:orgslug/explore/logs/) page and filter by service, environment, or search keywords to view log entries from your application. For an interactive UI walkthrough, click [here](https://docs.sentry.io/product/logs.md#overview).
* Open the [**Application Metrics**](https://sentry.io/orgredirect/organizations/:orgslug/explore/metrics) page to view and analyze your metrics. For more details, see this [interactive walkthrough](https://docs.sentry.io/product/metrics.md#overview).

## [Options](https://docs.sentry.io/platforms/python/integrations/flask.md#options)

In stream mode, these options still work as described, but apply to service spans instead of transactions.

Add `FlaskIntegration` explicitly to your `sentry_sdk.init()` call to set options for `FlaskIntegration` to change its behavior:

```python
import sentry_sdk
from sentry_sdk.integrations.flask import FlaskIntegration

sentry_sdk.init(
    # ...
    integrations = [
        FlaskIntegration(
            transaction_style="url",
            http_methods_to_capture=("GET",),
        ),
    ],
)
```

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

### [transaction\_style](https://docs.sentry.io/platforms/python/integrations/flask.md#transaction_style)

| Type    | `string`     |
| ------- | ------------ |
| Default | `"endpoint"` |

How to name transactions that show up in Sentry tracing. The default is `"endpoint"`.

In the code example, the transaction name will be:

* `/myurl/<foo>` if you set `transaction_style="url"`
* `myendpoint` if you set `transaction_style="endpoint"`

```python
    @app.route("/myurl/<foo>")
    def myendpoint():
        return "<p>Hello, World!</p>"
```

### [http\_methods\_to\_capture](https://docs.sentry.io/platforms/python/integrations/flask.md#http_methods_to_capture)

| Available since | `2.15.0`                                                         |
| --------------- | ---------------------------------------------------------------- |
| Type            | `Tuple[str, ...]`                                                |
| Default         | `("CONNECT", "DELETE", "GET", "PATCH", "POST", "PUT", "TRACE",)` |

A tuple containing all the HTTP methods (as uppercase strings) that should create a transaction in Sentry. The default is `("CONNECT", "DELETE", "GET", "PATCH", "POST", "PUT", "TRACE",)`.

Note that `OPTIONS` and `HEAD` are excluded by default.

## [Next Steps](https://docs.sentry.io/platforms/python/integrations/flask.md#next-steps)

At this point, you should have integrated Sentry into your Flask application. Here's what to explore next:

* Explore [practical guides](https://docs.sentry.io/get-started/guides.md) on what to monitor, log, track, and investigate after setup
* [Set up Agent Tracing](https://docs.sentry.io/platforms/python/agent-tracing.md) to monitor your AI systems
* Learn how to [manually capture errors](https://docs.sentry.io/platforms/python/usage.md)

Are you having problems setting up the SDK?

* Find various topics in [Troubleshooting](https://docs.sentry.io/platforms/python/troubleshooting.md)
* [Get support](https://www.sentry.help/en/)