---
title: "Automatic Instrumentation"
description: "Learn what transactions are captured after tracing is enabled."
url: https://docs.sentry.io/platforms/dart/tracing/instrumentation/automatic-instrumentation/
---

# Automatic Instrumentation | Sentry for Dart

Capturing transactions requires that you first [set up tracing](https://docs.sentry.io/platforms/dart/tracing.md) if you haven't already.

### [http.Client Library Instrumentation](https://docs.sentry.io/platforms/dart/tracing/instrumentation/automatic-instrumentation.md#httpclient-library-instrumentation)

The `http.Client` instrumentation, once added the `SentryHttpClient` and enabled the [performance](https://docs.sentry.io/platforms/dart/tracing.md) feature, starts a span out of the active span bound to the scope for each HTTP Request. The SDK sets the span `operation` to `http.client` and `description` to request `$METHOD $url`; for example, `GET https://sentry.io`.

The span finishes once the request has been executed. The span `status` depends on either the HTTP Response `code` or `SpanStatus.internalError()` if the `code` does not match any of Sentry's `SpanStatus`.

When the HTTP request throws an `Exception`, Sentry's SDK associates this exception to the running span. If you haven't set the SDK to swallow the exception and capture it, the span and `SentryEvent` will be linked when viewing it on the **Issue Details** page in sentry.io.

For more information see our [SentryHttpClient integration](https://docs.sentry.io/platforms/dart/integrations/http-integration.md#performance-monitoring-for-http-requests).

### [Dio HTTP Library Instrumentation](https://docs.sentry.io/platforms/dart/tracing/instrumentation/automatic-instrumentation.md#dio-http-library-instrumentation)

The Dio instrumentation starts a span out of the active span bound to the scope for each HTTP request. The SDK sets the span `operation` to `http.client` and the `description` to request `$METHOD $url`. For example, `GET https://sentry.io`.

The span finishes once the request has been executed. The span `status` depends on either the HTTP response `code` or `SpanStatus.internalError()` if the `code` does not match any of Sentry's `SpanStatus` options.

When the HTTP request throws an `Exception`, Sentry's SDK associates this exception to the running span. If you haven't set the SDK to swallow the exception and capture it, the span and `SentryEvent` will be linked when viewing it on the **Issue Details** page in [sentry.io](https://sentry.io).

Learn more in our [Dio integration documentation](https://docs.sentry.io/platforms/dart/integrations/dio.md#performance-monitoring-for-http-requests).

### [File I/O Instrumentation](https://docs.sentry.io/platforms/dart/tracing/instrumentation/automatic-instrumentation.md#file-io-instrumentation)

The Sentry-specific file I/O implementation starts a span out of the active span, bound to the scope for each file I/O operation. The SDK sets the span `operation` to `file.copy`, `file.write`, `file.delete`, `file.open`, `file.read` or `file.rename`, and `description` to `filename` (for example, `file.txt`).

In addition, the span contains other useful information such as `file.size` (raw number of bytes), `file.path` (an absolute path to the file), and `file.async` (`true` if the called method returns a `Future`, or `false` if it's a `Sync` call) as part of the `data` payload.

The span finishes once the operation has been executed. The span `status` is then set to `SpanStatus.ok` if successful, or `SpanStatus.internalError` if there was an error.

When the operation throws an `Exception`, Sentry's SDK associates it with the running span. If you haven't set the SDK to swallow and capture the exception, the span and `SentryEvent` will be shown as linked on the **Issue Details** page in [sentry.io](https://sentry.io).

For more information see our [file I/O integration](https://docs.sentry.io/platforms/dart/integrations/file.md).