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. Where to find your GA4 Property ID In the GA UI: 1. Open Google Analytics → bottom-left Admin (gear). 2. In the Property column, click Property settings. 3. Copy Property ID — it’s a numeric value (e.g., 481356553). From the URL (quick way): When you’re inside the GA4 property, the URL looks like: …/analytics/web//p123456789/… → the digits after p are your Property ID (123456789 in this example). What not to use: Measurement ID (looks like G-XXXXXXX) — that’s the data stream ID, not the property ID. Universal Analytics IDs (UA-XXXXX-Y) — those are legacy and won’t work with GA4 Data API. In this template: Put that numeric ID into the Set → PROPERTYID field. The HTTP node path properties/{{ $json.PROPERTYID }}:runReport expects only the number, no prefixes. How to set up 1. Open the Set (Define variables) node and fill: PROPERTYID, LOOKBACKDAYS, ALERTPCT, ZTHRESHOLD, CHANNELDIM, ALERTME. 2. Connect your Google Analytics OAuth2, Slack, and Email credentials. 3. In Email Send, map Subject → {{$json.emailSubject}} and HTML body → {{$json.emailHtml}}. Keep Execute once enabled. 4. Run the workflow. How to customize Change the moving-average window (WINDOW/MAWINDOW) and chart range (LASTNDAYSCHART). Swap CHANNELDIM (e.g., source/medium) to analyze different dimensions. Add/remove metrics in the GA4 request and the metrics list in the Code node. Tweak thresholds to reduce noise: raise ZTHRESHOLD or ALERTPCT. Output example !Screenshot 20250826 at 18.32.15.png(fileId:2202)