How to see what changed on a web page
Sometimes you notice a page looks different and want to know exactly what moved. A price, a sentence in the terms, a product that's gone. If you weren't already watching it, you can still find out. This guide covers where old copies of pages live, how to compare them, and how to make sure you never have to go digging again.
Look for a page history first
Some pages record their own changes. Wikipedia keeps every edit. Many software companies publish a changelog. Terms and privacy pages often show a Last updated date, and the better ones keep a list of what changed in each version. Check the bottom of the page before anything else.
A date on its own is only a clue, though. It tells you something changed, not what.
Use the Internet Archive's saved copies
The Internet Archive's Wayback Machine has saved copies of a huge number of public pages, going back years. Paste an address into it and you'll see a calendar of the days it was saved. Open an old copy and compare it with the live page.
It's free and very useful, with some limits:
- Popular pages are saved often; small sites may only be saved now and then
- Pages that load their content with JavaScript sometimes save badly
- Comparing two long pages by eye is slow, and small edits are easy to miss
Compare the two versions properly
Reading two versions side by side works for a short page. For anything longer, a comparison tool is faster: it lines the versions up and shows only what's different.
ChangeGist's free What changed tool does this for you. Paste an address, choose a week, a month or a year ago, and it fetches the Internet Archive's copy from then, compares it with the page today, and explains the differences in plain English, such as “Price went up from £24 to £28”. There's no sign-up, and it never visits sites that ask not to be checked automatically.
When there's no saved copy
If no one saved the page, the old version may be gone. A few places are still worth a look: your own browser history and any screenshots you took, emails from the company announcing the change, and search engine results, whose short descriptions are sometimes out of date in a helpful way.
If it's a page you depend on, such as a supplier's terms or a competitor's prices, this is the moment to start keeping your own record.
Never have to dig again
The simplest fix is to watch the page from now on. A monitoring service keeps a copy of every version and tells you when it changes, so the next time you wonder “when did they change that?”, the answer and the exact wording are already there.
For pages where the wording matters, such as terms, policies and official guidance, keep every version rather than just the latest. For prices, a running chart of every price seen is often more useful than any single change.