How to Get Alerted When GA4 Conversions Drop
To get alerted when GA4 conversions drop, create a custom insight in GA4 on the key events metric (GA4 now calls conversions "key events"), set the condition to "% decrease more than" a number you choose or to "Has anomaly", pick hourly evaluation, and add the email addresses to notify. It is free and takes about five minutes, but it checks processed data at most once an hour and only sends email. If you need to know within minutes, or in Slack, use a monitoring tool such as MetricsWatch Alerts, from $79 a month for 3 alerts checked every 15 minutes, or write your own script against the GA4 Data API.
Every Google limit on this page was checked against Google's own documentation on 30 October 2026. This guide is on the MetricsWatch blog, and MetricsWatch sells a GA4 alerting product, so where our product comes up we say what it does and what it costs, and we say where the free GA4 rule is enough.
Set up a conversion drop alert in GA4
- Open the Insights card. In your GA4 property, go to the Reports snapshot, find the Insights card and click View all insights. You need the Editor or Administrator role on the property.
- Click Create, then Create new under Start from scratch.
- Choose Hourly. The options are hourly, daily, weekly and monthly. Hourly is only available for web data; Google does not offer hourly custom insights for app events.
- Leave the segment on All Users for your first rule. Later you can click Change and narrow a rule to one dimension value, for example your paid traffic.
- Pick the key events metric and the condition. Use "% decrease more than" with a value such as 50, or "Has anomaly", which lets GA4 decide what is unusual from your own history.
- Name it, enter the email addresses to notify, and click Create. Everyone with access to the property also sees the insight on the Insights panel.
Our guide to GA4 custom alerts covers the same feature for traffic and other metrics.
Which rule catches a real drop
Key events decreased by more than 50 percent, hourly. This catches the drops that matter most: a tag removed in a Tag Manager publish, a thank-you page that moved, or a form that stopped submitting. Fifty percent is loose enough that a quiet afternoon does not trigger it.
Key events has anomaly, daily. Google trains its anomaly model on 90 days of history for daily checks and 2 weeks for hourly checks. A daily anomaly rule catches the slower slide that a fixed threshold misses, such as a campaign that quietly stopped converting.
A second rule on your most valuable segment. A total can hide a drop in one channel. If paid search stops converting while organic grows, the total may barely move.
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Three ways to get the alert
| Option | How often it checks | Where the alert goes | Limits | Price |
|---|---|---|---|---|
| GA4 custom insight | Hourly at best, on web data only, and on processed data: Google lists 2 to 6 hours for intraday data on standard properties | Email, and the Insights panel in GA4 | 50 custom insights per property; one metric and condition per rule; Editor or Administrator role to create | Free |
| Your own script on the GA4 Data API | As often as you schedule it; the realtime report covers the last 30 minutes | Wherever your script sends it | You build and maintain it; the realtime report supports fewer dimensions and metrics than standard reports | Free to call; your time to build and keep running |
| MetricsWatch Alerts | Every 15 minutes on Basic, 10 on Starter, 5 on Professional | Email on every plan; Slack from Starter | 3, 10 or 30 alerts per account | $79, $99 or $299 per account per month, or $790, $990 or $2,990 per year |
When the free GA4 rule is enough
If your site converts a few times a day and you check results each morning, the hourly custom insight plus a daily anomaly rule is enough, and you should set them up today whatever else you use. Both are free.
The GA4 rule falls short in three cases. First, when an hour of lost conversions costs real money, such as during a paid campaign or a sale. Second, when the person who can fix it lives in Slack and does not read alert email. Third, when the right threshold depends on the day: a rule tuned for a Tuesday afternoon fires every Sunday morning, and after a few false alarms people stop reading the emails.
What to check when the alert fires
- Realtime report. Are key events arriving at all right now? If none are arriving, it is a tracking problem, not a demand problem.
- The key event itself. In Admin, check that the event is still marked as a key event and that its name has not changed.
- Recent changes. A Tag Manager publish, a site release, a new consent banner or a form plugin update in the last day is the usual suspect.
- One channel or all. Compare paid, organic and email. A drop in one channel points at that campaign or its landing page; a drop everywhere points at the site or the tag.
Conversion drop alerts with MetricsWatch
MetricsWatch Alerts checks your GA4 data on a schedule and alerts you when a metric crosses a threshold you set, or when tracking stops. It watches traffic, conversions, events and custom metrics, and each alert can be filtered by source, medium, campaign, country, landing page or any other GA4 dimension. You can set different thresholds for weekdays and weekends and quiet hours when no alert is sent. Basic is $79 a month ($790 a year) for 3 alerts checked every 15 minutes by email. Starter is $99 a month ($990 a year) for 10 alerts every 10 minutes, by email and Slack. Professional is $299 a month ($2,990 a year) for 30 alerts every 5 minutes. The trial needs no credit card, and there is a 30-day money-back guarantee.
If you would rather see conversions in a client report than in an alert, MetricsWatch Reports emails a scheduled GA4 report with the full report in the email body, from $49 a month for 2 reports.
To try an alert on your own property, start at metricswatch.com/get-started.
Frequently asked questions
Can GA4 alert me when conversions drop?
Yes. Create a custom insight on the key events metric with a "% decrease more than" or "Has anomaly" condition and add email addresses for notifications. GA4 allows 50 custom insights per property.
What happened to conversions in GA4?
Google renamed them. Events that measure actions important to your business are now called key events, and a "conversion" is now an action you use to measure ad campaigns and optimize bidding, defined the same way in Google Ads and Analytics. When you build an alert in GA4, look for the key events metric.
How quickly will GA4 tell me conversions dropped?
An hourly custom insight is the fastest GA4 option, and it is only available for web data. It evaluates processed data, and Google lists 2 to 6 hours for intraday data on standard properties, so expect to hear in hours, not minutes.
Can GA4 send alerts to Slack?
Google documents email notifications and the Insights panel for custom insights; we could not find a Slack option documented. Getting an alert into Slack means forwarding the email or using a tool that posts to Slack directly.
Why do I get false alarms from GA4 custom insights?
A fixed threshold does not know about weekends, nights or campaign gaps. Loosen the threshold, move the rule to daily, or use "Has anomaly" so GA4 judges against your own history.
How much does a conversion drop alert cost?
The GA4 custom insight is free. MetricsWatch Alerts costs $79 per account per month for 3 alerts, $99 for 10 and $299 for 30, or $790, $990 and $2,990 per year.
