Why
PageSpeed isn't a snapshot.
If you only measure your load time at go-live, you fly blind afterwards. Core Web Vitals change with every update and every new piece of content, and Google keeps score without telling you. Search Console shows regressions only with weeks of delay, PageSpeed Insights only on manual demand. SiteSentry takes over the re-measuring so you don't have to. Why that matters for rankings, we explain on our PageSpeed monitoring page.
Features
What SiteSentry can do.
Automatic measurements
Check intervals from every two hours to once daily, configurable per website. The measurement runs in the background without anyone having to remember it.
Mobile & desktop
Every website is monitored as a mobile or desktop measurement, as you choose, because many problems only show up in one of the two variants, and Google evaluates mobile first.
Genuine Google data
Measurement runs through the official Google PageSpeed API on purpose: you see exactly the values Google itself reports, the four PageSpeed categories performance, SEO, accessibility and best practices, plus Core Web Vitals like LCP and CLS.
Thresholds & email alerts
You set your own threshold per metric, per category and separately for mobile and desktop. If it's breached, an email arrives immediately. No daily noise, just an active alert exactly when something really tips.
History & charts
Every measurement lands in a history with charts. You can see right away when a value degraded, and narrow down the trigger rather than guessing.
Free & bilingual
Register and go, no paywall. The interface and notifications are available in English and German, developed and operated by aceArt in Stuttgart.
Process
To monitoring in three steps.
Step 01
Register
Create an account with your email address and confirm it; nothing more is needed. If you like, set a separate notification address, say a team inbox.
Step 02
Add your website & thresholds
Enter the URL, choose the check interval and mobile/desktop, set thresholds for the metrics. Sensible suggestions are already in place.
Step 03
Alerts only in an emergency
From now on, SiteSentry measures automatically. You hear nothing until a value breaches your threshold. Then an email arrives, and the history shows you what happened.
FAQ
What we're asked about SiteSentry.
Is SiteSentry really free?
Yes. We built SiteSentry because we needed it for our own work, and we provide it free of charge. There's no paywall and no trial period that runs out.
What is measured, and with what?
SiteSentry measures through the official Google PageSpeed API, so you get exactly the data PageSpeed Insights also shows: the four PageSpeed categories (performance, SEO, accessibility, best practices) plus Core Web Vitals like LCP and CLS. As a mobile or desktop measurement, at intervals from every two hours to once daily.
How does that differ from PageSpeed Insights?
The data source is the same; SiteSentry uses the official PageSpeed API. The difference is the automation: PageSpeed Insights measures once, when you call it; SiteSentry measures regularly, stores the history and actively emails you as soon as a value breaches your threshold. Think blood pressure monitor versus long-term ECG.
Will I now get daily emails?
No, that's the point of the thresholds. An email only arrives when a monitored value breaches the limit you set. As long as everything is in the green zone, your inbox stays empty. You can also measure entirely without notifications and just use the history.
And if a value tips — then what?
The history shows you when the regression began. From there the trigger can usually be narrowed down quickly: an update, a new script, a large image. You can tackle the fix yourself or hand it to us: that's exactly our day-to-day business.
To the PageSpeed optimisation page
