How to get an alert when your website traffic drops

Option 1: a GA4 custom insight

Custom insights are GA4's own alerts. You write a condition, GA4 checks it on a schedule, and the insight appears on the Insights dashboard. Email is optional and set per insight (source 1).

1. 1

   Open the property's insights

   In GA4, open the property you want to watch and go to its insights, then choose to create a custom insight.

2. 2

   Choose how often it is checked

   Hourly, daily, weekly or monthly. Hourly checks are only available for web data; app data can only be checked daily or less often (source 1).

3. 3

   Set the condition

   Pick a metric such as sessions or active users and a condition such as a percentage decrease of more than 50%. You can limit it to a segment, for example one country.

4. 4

   Turn on email

   Name the insight, turn on email notifications and add the people who should receive them.

5. 5

   Repeat for every property

   Each insight belongs to one property, so every site you run needs its own.

Option 2: an uptime monitor

An uptime monitor requests your site every few minutes from outside and alerts you when it stops responding or returns an error. It is the fastest way to learn that a site is down. It can't see analytics at all, so a broken tag, a blocked consent setup or a slow decline in visitors passes unnoticed while every check stays green.

Option 3: silence alerts for every property

A silence alert works from the traffic itself. SilenceRadar learns each site's normal hours from its last seven days in GA4 and checks every watched property every 15 minutes. When a site has no visitors for longer than its threshold at a time it normally has them, or today is far below the same weekday last week, it loads the site and emails you either that the site is down or that the site is up but Google Analytics is receiving nothing. When visitors come back, a second message says so.

• Connect the Google accounts that can see your GA4 properties; every property is listed.
• Keep ticked the sites you want watched. Silence watch is on for them with a two-hour threshold.
• Change the threshold per site, from 30 minutes for busy sites to a day for small ones.
• Add more email addresses, a Slack channel or a webhook on the Alerts page.

The three side by side

Picking a threshold

A threshold that is too tight floods you with alerts on quiet afternoons; one that is too loose finds a broken tag days late. Compare like with like: this Tuesday with last Tuesday, at the same hour, rather than with yesterday. For a fixed GA4 condition, a drop of half or more against the same day last week is a reasonable start for a site with steady traffic. Very small sites, with a handful of visitors a day, are better watched over longer windows, since a few quiet hours are normal for them.

When the alert fires

• Load the site yourself. If it doesn't load, it's a hosting, DNS or certificate problem, not analytics.
• If it loads, open GA4 Realtime and visit the site. If you don't appear, the tag is the problem; the GA4 tag checker shows what the page loads.
• Check what changed most recently: a deploy, a theme or plugin update, Tag Manager, or the cookie banner.
• Once fixed, confirm visits appear in Realtime and annotate the gap in your reports.

Sources

• 1. Google Analytics Help, Analytics Insights: https://support.google.com/analytics/answer/9443595

Questions