An online price tracker runs in the cloud: you hand it a product URL, it checks the page on a schedule, and it messages you when the price moves, with nothing to install. Our pick is AyeWatch, because it reads any public product page, takes the condition in plain English, and on paid plans exposes the same monitors to your own code through a REST API, webhooks and an MCP server.
Online tracker, extension or store feature?
There are three common ways to watch a price, and they differ in where the checking happens.
| Approach | Where it runs | Coverage | Good for |
|---|---|---|---|
| Online tracker (AyeWatch) | On the service's side; you use the web app or phone app | Any public product page | Many stores, alerts on your phone or in your tools |
| Browser extension (Keepa, The Camelizer) | Your browser | Amazon | Amazon price history while you shop |
| Built-in feature (Chrome, Google Search) | Google's services, signed in | Products Google recognizes, in five countries | Quick tracking of mainstream products |
The online approach is the only one that does not care which store the item is on or which browser you use.
How an online tracker reads a price
The work is simple to describe. The tracker loads the page, finds the price for the variant you linked, compares it with your rule, and sends a message when the rule is met. The hard part is noise: pages change all the time for reasons that have nothing to do with price, such as a new banner, a reordered review list or a rotating promo.
AyeWatch uses AI that understands meaning instead of matching keywords, which cuts down on noisy alerts, so you can write a rule like "only tell me if the price for the 512 GB model drops below $899." When it fires, you get a short summary of the change and the link, not a diff.
Set one up in the browser
- Sign in at ayewatch.ai and choose to monitor a webpage.
- Paste the product URL, with the exact variant already selected.
- Write your rule.
- Pick a pace: Auto adjusts how often it checks to how busy the page is, or choose your own interval from the ones your plan allows.
- Choose where alerts go. Push and the feed are on every plan; email, Slack, Discord and webhooks are on paid plans.
The same monitors show up in the iOS and Android apps.
For developers: price monitors from code
This is where AyeWatch differs most from a shopping app. Every paid plan includes:
- A REST API to create, list, update and delete monitors, so a script can add a product URL when someone files a purchase request.
- Signed webhooks that deliver each update with its AI summary, ready to post into a channel or write to a table.
- An MCP server at
https://ayewatch.ai/api/mcp, documented in the AyeWatch MCP docs. Connect an assistant such as Cursor with your API key, and it can callcreate_topicwith web page URLs, orupdate_topicto pause a monitor once you have bought the item.
That turns "watch our vendors' pricing pages and tell the team channel when any price changes" into a short script rather than a manual chore.
What it will not do
AyeWatch reads public pages. It does not log in to stores, it does not buy anything, and it does not keep a long price chart.
When another approach fits better
If all you want to know is whether an Amazon deal is real, a history chart answers that at a glance, and Keepa draws one for you. If you already qualify for Chrome's built-in tracking and only buy mainstream products, switching it on costs nothing. An online tracker is worth it when your list spans several stores, or when the alert has to reach a script or a team instead of one person's browser.
Paid plans start at $9 a month as of November 2026, billed in monitoring credits, and a free preview lets you try it without a card.