Catch JavaScript errors with one script tag

A script tag in your site's <head> reports JavaScript errors from your visitors' browsers to Lampwick. It needs no package and no build step, so it also works in apps made with Lovable, Replit or v0.

What you get

• Uncaught errors and unhandled promise rejections, with the stack trace, under Issues with a Browser label.
• Optional: console.error calls (data-console) and failed fetch() calls (data-fetch).
• Page URLs without the query string and fragment, which often hold tokens.
• A monthly budget of its own for browser errors, on top of your plan's events.

Lampwick doesn't apply source maps, so stack frames show positions in your bundle.

Set it up

On the project's Settings page, under Browser errors, click Get the snippet. Copy the line into the <head> of your site's index.html, above the other scripts:

<script src="https://app.lampwick.dev/b.js" data-key="YOUR_BROWSER_KEY" async></script>

YOUR_BROWSER_KEY starts with lwpub_; the snippet on the Settings page has it filled in. The key is meant to be in your page: it can only send errors to this project.

To test it, open your site and run this in the browser console:

setTimeout(() => { throw new Error('Lampwick test') })

Let your app builder do it

Paste this into the chat of Lovable, Replit or v0, with your key in it (the Settings page has this prompt ready to copy):

Add the Lampwick error monitoring snippet to the <head> of index.html, exactly as written, before any other script:

<script src="https://app.lampwick.dev/b.js" data-key="YOUR_BROWSER_KEY" async></script>

Don't change the key or move it to an environment variable: it is a public, write-only key that is meant to be in the page. Don't wrap it in a component or install a package for it.

Next step

The browser errors docs cover the options, Allowed sites, the limits and troubleshooting.