Competitor Price Monitor — Price & Stock Change Alerts

Watch any competitor's product pages and get a clean, typed alert the moment something moves: a price drop, a restock, a sell-out, a sale starting or ending, a new or removed variant. This is a monitor, not a one-shot scrape — keep it on a schedule and each run reports only what changed since the last one, so you pay for signal, not for re-dumping the same catalogue every day.

What it does

On every scheduled run, for each product URL you give it:

1. Reads the product reliably. It first tries the store's own product endpoint (Shopify /products/<handle>.js — clean structured data with every variant's price, SKU and in-stock flag), then falls back to JSON-LD, OpenGraph/microdata, and finally a text parse. A resilient browser handles JS-only storefronts automatically. Every snapshot carries a parse_confidence so a degraded read is flagged, never silently mis-reported.
2. Compares against the previous run (state is persisted per URL in a named Key-Value store) and emits typed change events.
3. Builds a watchlist digest — cheapest in-stock item, a full price matrix, stock/sale counts, and this run's change summaries — one decision-ready record.

Outputs

Three record types land in the dataset (filter by record_type):

• snapshot — domain, title, price, currency, compare_at_price, in_stock, on_sale, lowest_price/highest_price, variants[] (each with price / compare-at / SKU / availability), parse_confidence, extraction_method.
• change_event — event_type, summary, previous_value, current_value, change_pct, direction, variant. Event types: price_changed, variant_price_changed, back_in_stock, out_of_stock, sale_started, sale_ended, title_changed, variant_added, variant_removed, page_changed_unparsed. (baseline_created is emitted on the first run of a URL and is informational, not billed as a change.)
• digest — one per run: cheapest_in_stock, price_matrix, in_stock_count, out_of_stock_count, on_sale_count, changes_by_type, change_summaries, notes.

Input

Field	What it does
productUrls	Product page URLs to monitor (Shopify, WooCommerce, BigCommerce, custom).
emitDigest	Emit the one-per-run watchlist digest (default on).
eventTypes	Restrict which change events are emitted/charged (empty = all).
kvStoreName	Named KV store that persists state between runs — keep it constant across scheduled runs.
forceBrowser	Always render in a browser (slower; normally auto-escalated only when needed).
proxyConfiguration	Apify Proxy; defaults to US residential so geo-localized prices stay stable run-to-run.

How to use it as a monitor

1. Add your competitors' product URLs and run once — this bootstraps a baseline (you'll see baseline_created records, no change events yet).
2. Schedule the actor (e.g. daily) with the same kvStoreName.
3. From the second run on, you get only the changes — wire the change_event records into your alerting (email, Slack, a webhook on new dataset items).

Reliability note

Keep the proxy country pinned (default US). A rotating exit country can serve a different currency for the same page, which would look like a price change and re-baseline your monitor. The actor already guards against a currency flip, but a pinned country keeps the data cleanest.

Pricing

Pay-per-event: one charge per product snapshot, one per change event emitted, one per watchlist digest. Platform compute runs on your own Apify account.