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 happens.

  category: "auth",
  message: "Authenticated user " +,
  level: Sentry.Severity.Info,

Automatic Breadcrumbs

SDKs will automatically start recording breadcrumbs by enabling integrations. For instance, the browser JavaScript SDK will automatically record all location changes.

  // ...

  beforeBreadcrumb(breadcrumb, hint) {
    return breadcrumb.category === "" ? null : breadcrumb;

Customize Breadcrumbs

SDKs customize breadcrumbs through the before_breadcrumb hook. This hook passes an already assembled breadcrumb and, in some SDKs, an optional hint. The function can modify the breadcrumb or decide to discard it entirely:

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

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