What Is the Tracy Bar and What Information Does It Show?

Tracy Bar is a debugging panel that sits in a PHP website and shows runtime information about that site. According to the Tracy project, it "can measure time, record memory, count database requests, and monitors all sorts of important data." It is part of Tracy, a PHP debugging tool that also handles error visualization, logging, and variable dumping. If you want a quick read on what a page actually did while it rendered — rather than guessing from log files — the Tracy Bar is the feature built for that.

What the Tracy Bar shows

The panel is described as "a wonderful source of priceless information about a website." The specific data points named by the project are:

• Time — measured while the site runs
• Memory — recorded during execution
• Database requests — counted
• Other important runtime data — monitored generally

That combination means the bar answers questions like "how long did this page take," "how much memory did it consume," and "how many database queries did it fire" without you adding your own instrumentation for each one.

How it fits with the rest of Tracy

Tracy Bar is one of several capabilities in Tracy, not the whole tool. The project groups its features around debugging PHP code:

The error side is worth noting because it is the most opinionated part of the tool. Tracy doesn't just print the PHP notice — it hints at the fix. The project's own example: a well-known PHP notice gets the addition "did you mean $greeting?" And beyond hinting, Tracy can apply the fix in one click. That is a deliberate design choice, and the project leans into it with the line "Warning: Tracy is addictive!"

Extending what the bar displays

The bar is not limited to its built-in measurements. The project states you "can enjoy it even more by plenty of plugins," which is the mechanism for adding panels or data sources beyond time, memory, and database request counts. So if the default set doesn't cover what you need to watch, the intended path is a plugin rather than modifying the core.

Maturity and who relies on it

Tracy has been in development "for over 18 years — and counting." The project describes its libraries as "highly mature, stable, and widely used," trusted by "a number of global corporations," with "many significant websites" relying on them. That matters if you're deciding whether to put a debugging tool into a production-adjacent workflow: the longevity is the argument the project makes for stability.

Where to go next

The site links to a demo of the Tracy Bar, plus Documentation and a GitHub repository. There is also a Forum and Discord for support. If you want to see the panel's output before installing anything, the demo is the fastest way; if you want to know what a given panel measures or how to write a plugin, the documentation is the reference.