Breadcrumbs

Sentry uses breadcrumbs to create a trail of events that happened prior to an issue. These events are very similar to traditional logs, but can record more rich structured data.

This page provides an overview of manual breadcrumb recording and customization. Learn more about the information that displays on the Issue Details page and how you can filter breadcrumbs to quickly resolve issues in Using Breadcrumbs.

Manual Breadcrumbs

You can manually add breadcrumbs whenever something interesting happens. For example, you might manually record a breadcrumb if the user authenticates or another state change occurs.

You'll first need to import the SDK, as usual:

import * as Sentry from "@sentry/react-native";

Manually record a breadcrumb:

Sentry.addBreadcrumb({
  category: "auth",
  message: "Authenticated user " + user.email,
  level: "info",
});

The available breadcrumb keys are type, category, message, level, timestamp (which many SDKs will set automatically for you), and data, which is the place to put any additional information you'd like the breadcrumb to include. Using keys other than these six won't cause an error, but will result in the data being dropped when the event is processed by Sentry.

You can choose from the following breadcrumb log levels: "fatal", "critical", "error", "warning", "log", "info", and "debug".

Automatic Breadcrumbs

The React Native SDK captures breadcrumbs automatically using the native Android and iOS SDKs:

• Automatic breadcrumbs for Android
• Automatic breadcrumbs for iOS

More breadcrumbs can be captured by the React Native SDK:

• For interaction breadcrumbs, wrap your root component using the Sentry.wrap method.
• For navigation breadcrumbs, use one of the SDK's navigation integrations.
• HTTP requests are included in breadcrumbs by default.
• To track redux actions and latest store state, use Sentry.createReduxEnhancer.

Customize Breadcrumbs

SDKs allow you to customize breadcrumbs through the beforeBreadcrumb hook.

You'll first need to import the SDK, as usual:

import * as Sentry from "@sentry/react-native";

This hook is passed an already assembled breadcrumb and, in some SDKs, an optional hint. The function can modify the breadcrumb or decide to discard it entirely by returning null:

Sentry.init({
  // ...
  beforeBreadcrumb(breadcrumb, hint) {
    return breadcrumb.category === "ui.click" ? null : breadcrumb;
  },
});

For information about what can be done with the hint, see Filtering Events.