Ga4 anomaly detection with automated Slack & email alerts

Who’s it for

Teams that monitor traffic, signups, or conversions in Google Analytics 4 and want automatic Slack/email alerts when a channel suddenly spikes or drops.

What it does

This n8n template pulls daily GA4 metrics, detects outliers with a rolling mean and z-score, and sends alerts with a sparkline chart. It supports per-channel analysis (e.g., sessionDefaultChannelGroup) and consolidates multiple anomalies into a single email while posting each one to Slack.

How it works

HTTP Request (GA4 Data API) fetches sessions, newUsers, conversions, bounceRate by date + channel. Code calculates 7-day moving average and z-scores, flags anomalies, and builds QuickChart links. If filters on alert === true and optional ALERTME toggle. Slack posts an alert + chart. Email sends one summary email (subject + HTML table + charts).

Requirements

GA4 OAuth2 credential in n8n. Slack API credential (bot with chat\:write). Email credential (SMTP or service). GA4 property ID and at least several recent days of data.