Google Sheets KPI Prometheus Exporter for Grafana via n8n Webhook

Turn KPI rows in Google Sheets into live Prometheus metrics for Grafana—using an n8n Webhook exporter

This n8n workflow exposes KPI values stored in a Google Sheets document as a Prometheus text exposition endpoint, so Grafana can scrape and chart them. It adds caching, validation/normalization, and built-in exporter health metrics—delivered securely via an authenticated webhook.

What this workflow does

• Receives Prometheus scrape requests through an n8n webhook protected with header authentication (e.g., Authorization: Bearer <token>).
• Uses in-workflow caching: if the cached Prometheus body is still within the configured cache_ttl_seconds, it immediately returns the cached response.
• Reads KPI rows from Google Sheets when the cache is stale, pulling from a configured spreadsheet and tab.
• Validates and normalizes each metric row (metric name, type, numeric value, and labels). Malformed, duplicate, or over-limit series are dropped, and reasons are tracked as comments/metadata.
• Renders Prometheus 0.0.4 text format, updates the cache, and appends exporter self-metrics (including up status, cache hit/age, and row/series counts).
• Returns plain-text metrics to Prometheus, with optional behavior to serve stale cached data and/or return a configurable HTTP status code if the sheet read fails.

Use cases

• SaaS operators want KPI dashboards in Grafana without building a custom metrics service.
• Automation engineers maintain KPIs in Google Sheets, while Prometheus/Grafana handles monitoring and visualization.
• Teams need a lightweight Prometheus exporter pattern backed by spreadsheet-managed data.

Technical details

• n8n nodes: webhook, google sheets, code, if, set, plus supporting sticky note.
• Expected Google Sheets columns: metric_name, help, type, value, labels.
• Exporter configuration includes: Google Sheet ID, tab name, cache_ttl_seconds, max_series, exporter_prefix, and error behavior.