In today's video, we will explore browser monitoring, a core feature of Blackfire's front-end observability.
Browser monitoring provides visibility to how real users experience websites. It captures real world data, from real browsers, not synthetic tests.
You will track five key performance metrics. Let's break them down:
T.T.F.B., or Time to first bite: this is how long the browser waits before receiving the first bite of data from your server.
Lower is better. Aim under 200 milliseconds
L.C.P. or Largest Contentful Paint: This measures when the main content like a hero image or headline, finishes loading.
It tells users the page is mostly here. Aim for under 2.5 seconds.
C.L.S. or Cumulative Layout Shift. This tracks how much the page jumps around while loading.
A low score means a stable layout. Try to keep CLS below 0.1
Each metric reveals something different about the user experience: when content appears on the screen? How stable the language remains, as the page loads, and how fast the site feels when user try to interact with it?
If even one of this is off, your users will feel it.
Browser monitoring also shows you geographic performance. You can quickly see where users are struggling.
The geographic map helps you prioritize improvement by showing you where performance issues are most concentrated.
Each metrics links directly to Blackfire full stack view.
Click on the slow L.C.P. and you can see the backend trace that contributed to it. No more jumping between tools
And just like for all of Blackfire, Browser Monitoring is privacy-first.
It does not track individuals, store cookies or collect any personally identifiable information or P.I.I.. This means you don't need cookie banners. Your setup is GDPR-compliant by default, and user consent flow remains completely unaffected.