Hey Product Hunt 👋 I'm Giacomo, and filo is my open-source PHP call tracer: an Xdebug alternative that doesn't need an extension. Why I built it: every time I wanted to know why a request was slow, the answer was "install Xdebug". That means a PECL extension, php.ini edits, IDE setup, and a slower app while it's loaded. I wanted something I could add with Composer and switch on with a file. How it works: 📦 composer require --dev giacomomasseron/filo 📄 Create an empty .filo-on file in your project root. Every request (or CLI command) now writes a trace. Delete the file to stop, no restart needed. 🔥 vendor/bin/filo serve opens a local viewer: flamegraph, call tree with self-time, and a top-functions table where repeated calls (hello, N+1) jump out. Under the hood it's pure PHP. It rewrites your code on the fly as it's loaded and runs the instrumented copy from a cache. Your files are never touched. PHP 8.1+, any Composer project. Also included: ⏸️ Breakpoints by function name. The request pauses, you inspect its arguments and $this in the browser, then hit continue. Pause time is left out of the timings. ✅ Performance checks for Pest and PHPUnit, e.g. expect(fn () => $service->list())->toCall('App\Repo::find')->atMost(1) to catch an N+1 in CI before it ships. Honest limits: breakpoints fire only on function entry (no stepping, that's still Xdebug's job), and for now opcache has to be off while you trace. The name: filo is Italian for "thread", as in Ariadne's thread, the one that leads you out of the labyrinth. Here, the labyrinth is your call stack. It's MIT-licensed and free. I'd love to hear what you'd trace first, and what's missing: Laravel/Symfony integrations, sampling for staging, exporting to other profilers?

filo - no-extension call tracer for PHP

Trace & debug your PHP app. No Xdebug, no extensions

Trace & debug your PHP app. No Xdebug, no extensions