Price tracking browser extensions: are they safe to install?

Some price tracking extensions are genuinely useful. Others quietly harvest your browsing data or inject affiliate links into every page you visit. Here's how to tell the difference before you click install.

What these extensions actually do

A price tracking extension typically sits in your browser toolbar and does one of two things: it shows you a price history chart for the product page you're currently viewing, or it automatically applies coupon codes at checkout. Both are useful in theory. The problem is what the extension needs access to in order to do that job, and what it does with that access beyond the stated purpose.

To show you price history or apply codes, an extension generally needs permission to read and modify the pages you visit — which, by design, means it can see everything you do in your browser, including on sites that have nothing to do with shopping.

The permissions to actually check

Before installing anything, look at what permissions it requests. This is the single most useful five minutes you can spend.

• "Read and change all your data on all websites" — common for legitimate price trackers, but also the permission abused by malicious extensions to inject ads, swap affiliate links, or log form data on banking and email sites.
• Developer identity and update history — an extension with a long track record and a known, contactable developer is lower risk than an anonymous one that appeared last month.
• Review patterns — a sudden spike of generic five-star reviews after a long gap often means the extension changed ownership and is now being used differently than it was originally built for. Extension ownership changes are a known route for injecting tracking or ad-fraud code into a previously trustworthy tool.

Signs an extension has gone bad

Extensions can be sold or handed off between developers without much visibility to users. A tool that was safe when you installed it can change behaviour after an update. Watch for:

• Unexpected pop-ups or new tabs opening on unrelated sites.
• Links that redirect through unfamiliar domains before reaching their destination.
• The extension suddenly requesting new permissions it didn't need before.
• A noticeable slowdown in page loading, which can indicate background scripts running on every page.

A safer default

If you mainly want to compare prices before buying, doing that comparison on a dedicated site rather than through a permanently installed extension reduces your exposure considerably. Reserve extensions for tools you trust completely and use often enough to justify the access they're asking for.