Monitoring web pages for changes: Wayback Machine, Visualping, changedetection.io and Vite Research

Archive it: Wayback Machine

The Internet Archive's Save Page Now stores a public capture of a page on request. It is free, needs no account, and the capture is citable by its own address. It does not tell you when the page changes; you would compare captures yourself.

Watch it: dedicated monitors

• Visualping: free plan of 5 pages checked every 60 minutes; paid plans from $14 a month (10 pages every 15 minutes) upward, from its pricing page.
• Distill.io: free plan of 25 monitors, 5 of them in the cloud at a minimum interval of 6 hours; Starter $15 a month for 50 monitors every 10 minutes.
• changedetection.io: open source and self-hostable; the hosted plan is $8.99 a month for up to 5,000 URLs with re-check times from about 5 minutes.

These tools are built for frequency and volume: price pages, stock, tenders. They alert you; they do not keep a citable copy with a hash, nor tie the change to the passage you quoted.

Keep and watch it: Vite Research

Saving a page to the Library stores a snapshot with a SHA-256 hash and extracts the metadata. Monitoring is optional per source: manual or monthly checks on the free plan (5 monitored sources), weekly, daily or six-hourly on Pro. A change lands in the Changes inbox with a diff, a change ratio and a severity; from there you can save the new version as a snapshot, add a note, mark it reviewed or stop monitoring. E-mail alerts go out above a severity threshold. The citation warns when the source changed after it was created.

Which to use

Wayback for a free public record; a monitor for high-frequency watching of many pages; Vite Research when the page is a source in your work and you need the copy, the citation and the change history together.