Structured Product Price & Stock Monitor — JSON-LD / Shopify

Product Price & Stock Monitor: restock and price-drop alerts from a store's own data

Give it a list of product page URLs and it checks each one on a schedule, remembers what it saw last time, and tells you what moved. Price up or down, back in stock, out of stock, a sale starting or ending, or the title changing under the same link.

It reads the structured data a store publishes about its own products: JSON-LD, Shopify's product JSON, WooCommerce data, or microdata. No HTML selectors to break. The flip side is the honest limit: a store that publishes none of that returns nothing useful, and you get a row saying exactly that.

🛒 What Product Price & Stock Monitor does

Each run fetches every product URL, pulls the structured record out of the page, and compares it against the baseline it saved last time. The baseline lives in a named key-value store on your own account, so it survives between scheduled runs.

Six kinds of change are detected, and you can switch each family off: price_change, back_in_stock, out_of_stock, sale_started, sale_ended and title_change. A title change is the one people forget to watch, and it is how you catch a listing that has been quietly swapped for a different product under the same URL.

priceDropThresholdPct is worth understanding before you set it. At the default 0 every price move is recorded. Set it to 5 and a drop smaller than 5% is not reported, and the baseline still moves to the new price. So a product sliding 4% a run will never trip a 5% threshold, however far it falls in total. Price rises are always recorded whatever you set. If you want to catch slow slides, leave the threshold at 0 and filter on priceChangePct yourself.

Alerts go out through webhookUrl. Slack and Discord formats are detected from the URL, and anything else gets the full JSON payload, which is what Zapier, Make and n8n want.

📥 What you give it

{
  "products": [
    { "url": "https://www.adafruit.com/product/3055", "label": "Raspberry Pi 3" },
    { "url": "https://www.allbirds.com/products/mens-wool-runners", "label": "Wool Runners" }
  ],
  "priceDropThresholdPct": 0,
  "onlyNewSinceLastRun": true,
  "webhookUrl": ""
}

📤 What you get back

A real row from a recent run:

{
  "target": "snap-www.adafruit.com-fda349aa961c",
  "label": null,
  "url": "https://www.adafruit.com/product/3055",
  "checked_at": "2026-08-22T07:52:20.183033+00:00",
  "extraction_status": "ok",
  "extraction_method": "json-ld",
  "sync_status": "ok",
  "current": {
    "title": "Raspberry Pi 3 - Model B - ARMv8 with 1G RAM",
    "price": 35,
    "currency": "USD",
    "list_price": null,
    "on_sale": false,
    "availability_raw": "http://schema.org/InStock",
    "in_stock": true,
    "sku": "3055"
  },
  "changes": [],
  "change_count": 0,
  "is_new": false,
  "is_changed": false,
  "error": null
}

🧾 Reading the output

Two kinds of row can land in your dataset.

On a quiet run with onlyNewSinceLastRun on, the only row you get is the notice, which reads status: "no_changes" and counts what was checked. That row is never billed.

Two things to know about status. A URL that answers with an HTTP error comes back with extraction_status: "error" and is not charged. And a page that answers normally but carries no structured data comes back as no_structured_data, which also covers a consent or interstitial page that answered in place of the product, so check the URL in a browser if a store you expect to work reports it.

▶️ How to run it

1. Open Product Price & Stock Monitor and click Try for free. 2. Put your product URLs into Products to monitor, one object each, with a label you will recognise in an alert. 3. Turn Only new / changed since last run off for the first run so you can see the full shape. 4. Run it once, check the rows, then turn it back on. 5. Paste a Slack or Discord hook into Webhook URL and schedule it.

💰 How much does it cost?

$0.0025 per product checked. Flat on every Apify plan, no volume tiers. When something moves:

A product gets at most one change event per run, whatever moved. A URL that answers with an HTTP error is not charged at all, and the quiet-run notice row is free.

💡 What people use it for

• Watching a sold-out item and getting a Slack ping the minute it is back, which is what

back_in_stock plus notifyOnRestock is for.

• Tracking a competitor's list prices across a few dozen product pages, with the threshold at 0 so

nothing is missed.

• Catching a supplier quietly relisting a different item under the same URL, using title_change.
• Watching when seasonal sales start and end across a set of stores, with sale_started and

sale_ended.

• Feeding a repricing sheet through the webhook, keyed on target.

🚧 What it does not do

• It needs the store to publish structured product data. No JSON-LD, Shopify, WooCommerce or

microdata means no usable row.

• No HTML fallback. That is the design: selectors break silently and give you wrong prices.
• A price-drop threshold moves the baseline anyway, so a slow slide under the threshold is never

reported. Leave it at 0 if that matters.

• No product search or discovery. You supply the URLs.
• No variant-level tracking. It reads the product record the page publishes, not every size and

colour.

• No stock counts, only in stock or not, because most stores publish only that.
• No screenshots and no price history chart. The history is whatever you keep from the rows.
• The product list has no cap in the schema, so a very long list can run out of time. Split it

across several scheduled runs.

🧭 Which monitor do you need?

❓ Questions people ask

Will it work on any store? Only on stores that publish structured product data, which is most Shopify and WooCommerce shops and a lot of others. Test one URL before you build a list on it.

How does it remember the last price? A named key-value store on your own account holds the baseline between runs. Nothing is kept on our side.

What happens the first time? Every product is new, so you get a full snapshot and no change events. Changes start from the second run.

Can I get Slack alerts? Yes, paste your Slack hook into webhookUrl and the format is picked up automatically. Discord too.

Why did a price drop not alert me? Check priceDropThresholdPct. A drop under the threshold is suppressed, and the baseline still moves.

Is monitoring public product pages legal? They are public pages and the data is what the store publishes about itself. Apify's write-up on scraping and the law is a sensible starting point, and we are not lawyers.

🆘 If something breaks

Open the Issues tab on the actor page. Send the run ID and the product URL. The row's extraction_status and extraction_method usually narrow it down on their own.