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Browser monitoring is a beta AppSignal Labs feature. The @appsignal/browser package is published under the beta tag on npm, and its configuration and API may still change between beta releases. Share feedback in our Discord community.
Browser monitoring reports what happens in your users’ browsers: front-end errors with the trail of events that led up to them, and Core Web Vitals measured on real page loads. It is a separate section in AppSignal, alongside the traces, errors, and metrics your back-end integration reports. Data collection is handled by @appsignal/browser, a standalone package that does not depend on any other AppSignal package.

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What it collects

Errors

Uncaught exceptions and unhandled promise rejections, with stack traces, tags, and the route the user was on.

Breadcrumbs

An automatic timeline of navigation, selections, network calls, and console output before each error. No setup needed.

Web vitals

LCP, INP, CLS, FCP, and TTFB from real users, aggregated per route and comparable across releases.

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Where to find it in AppSignal

The Browser section of your application has two views: Front-end errors are reported to the browser namespace, which keeps them out of your back-end error lists and notification settings. For what browser monitoring covers as a feature, see the browser monitoring overview.

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Relation to AppSignal for JavaScript

@appsignal/browser replaces @appsignal/javascript and its plugin packages. It is not a drop-in upgrade: the API is different, breadcrumbs and web vitals are collected without configuration, and errors are reported to the browser namespace instead of frontend. The old package keeps working, but new features only land in the new one. The migration guide maps the old API onto the new one.

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Requirements

  • A browser that supports ES2020. The package targets ES2020 and does not ship polyfills.
  • CLS and INP need Chromium’s layout-shift and event-timing performance entry types. Other browsers report LCP, FCP, and TTFB only.
Optional: React 16.8 or later, if you want to use the error boundary shipped with the package.

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Next steps

Install the package

Add @appsignal/browser to your application and start reporting.

Configuration options

Every option, its type, and its default.

Filter what you send

Scrub URLs, mask elements, and gate collection on user consent.

Migrate from AppSignal for JavaScript

Map the old API onto the new one.