Privacy
Nothing you type leaves your browser. The playground runs PHP inside your browser: the pattern and the text you test are never sent anywhere. A link you share carries them after the #, the part of an address browsers never send to a server.
No cookie. The site counts visits with Google Analytics, every consent setting denied before its script loads, so it stores nothing on your device. For each page, a cookieless request reaches Google with the page path, never what you type: the address it reports stops before the #.
Besides page views, it counts a few gestures in the playground, with the details named here and nothing else:
run: the Run button or Ctrl/⌘ Enter, withtrigger(button or keyboard)example_loaded: an example opened, with itsexample_namefinding_opened: a finding opened, with itsfinding_idshare_clicked: a finding’s link copied or shared, with itsfinding_idand themethod(copy or the device’s share sheet)voice_toggled: the tree switched to plain English or back, with thevoicechosenversion_changed: another PHP version picked, with thatphp_version
None of them carries a pattern, a text or anything else you typed.
Retention and the rest. Google Analytics keeps event-level data 14 months, then deletes it; its aggregated reports (how many visits, how many runs) are not bound by that setting. Google Signals is off, so nothing is joined to a Google account. The site has no account, no form and no newsletter.
The playground downloads PHP, compiled to WebAssembly, from cdn.jsdelivr.net the first time you ask it for an answer: typing a pattern or a text, pressing Run, opening an example or a finding. The step trace downloads PCRE2’s own module when you open its tab. jsDelivr sees those requests like any download.
Questions: open an issue.