Monitor competitor prices and stock with Gemini, Google Sheets and Slack alerts

Quick overview

Checks competitor product pages daily, reads price and stock from structured data (Gemini only when needed, with a text fallback), logs every check to Google Sheets and pings Slack only on real price moves or stock changes. Includes dedupe, configurable thresholds, an Errors tab and a run summary.

How it works

1. A daily schedule reads your Watchlist and History tabs, drops duplicate or inactive rows and skips URLs checked in the last few hours.
2. Each page is checked one at a time with a polite pause: a keyless demo extractor API first, then a direct page fetch that reads JSON-LD, meta tags and microdata.
3. Pages without structured data go to Gemini with a strict schema; if Gemini fails, the price is read from the page text instead.
4. Each result is compared with the last known price. Slack is alerted only when the price moves by at least your threshold or stock changes; low-confidence reads are logged, not alerted.
5. Every check is appended to History. Failed checks and Sheets/Slack errors go to an Errors tab, and a short run summary is posted to Slack.

Setup

1. Create a Google Sheet with Watchlist, History and Errors tabs (headers are listed in the yellow note).
2. In the Config node set sheetId and slackChannelId; optionally adjust minChangePct, minConfidence, minHoursBetweenChecks and runSummary.
3. Add Google Sheets, Slack and Google Gemini credentials.
4. Execute once to record a baseline, then activate.
5. Save the workflow and verify the Config node holds your own sheetId and slackChannelId before activating the trigger.

Additional info

Built with built-in nodes only, tested on n8n 2.43. No credentials or real IDs included. The demo extractor endpoint needs no key (10 pages a day). The Pro version adds undercut alerts with suggested reprices, room-to-raise and market rank, Apify for JavaScript-heavy shops, a Latest dashboard tab and a weekly summary: https://mohabaha0.gumroad.com/l/price-monitor-pro