Scrutoscope – WordPress Performance Profiler

TL;DR: Negligible overhead on non-profiled requests (a few ms). During active profiling, roughly 100–200 ms per request depending on your setup. There are two kinds of overhead. An always-on check on every request — a few milliseconds — decides whether the request is being profiled; this is what every visitor pays, and it's negligible. When a request is being profiled (an admin session, or the sampled fraction of background traffic), instrumenting the hooks and timing every callback adds roughly 100-200ms in our benchmarks (closer to 100ms in Lightweight Mode, closer to 200ms with the full trace). Both vary a lot with your environment — number of active plugins, OPcache, whether MySQL is local or remote, your hardware, and current load — so we report what we measured rather than promising a number. Background measurement is off by default; when you turn it on you choose the sample rate, and at a low rate most requests only pay the few-ms check. Query detail is a separate opt-in: enabling Query Profiling turns on WordPress SAVEQUERIES, which makes WordPress keep query text, timing, and caller in memory for the request — extra overhead you only pay when you ask for query detail, so leave it off when you just need request and source timing. And you're always one click from zero: deactivating Scrutoscope removes all overhead and keeps your captured profiles (only deleting the plugin removes the data).

Nothing, unless you choose to share a report. The "Send to Support" feature encrypts your report in the browser before upload. The relay server never sees your data. No telemetry, no analytics, no phone-home.

Yes. Scrutoscope profiles any WordPress request, including WooCommerce pages, AJAX calls, and REST API endpoints.

Yes, with a low sample rate (0.1% or 1%). Scrutoscope is designed for background capture at scale. Use higher rates for focused debugging.