Internet Archive Change Explorer

How it works

Lists the distinct Wayback Machine captures of a URL, picks the captures closest to two dates (or exact timestamps), fetches both raw archived versions and diffs them, ranking meaningful changes — prices, headings, legal/policy terms, dates, contacts, links — above noise. Paste CDX rows and two HTML versions to analyse offline.

• Capture list: Wayback CDX API GET https://web.archive.org/cdx/search/cdx?url=…&output=json&fl=timestamp,original,statuscode,digest,length,mimetype&filter=statuscode:200&filter=mimetype:text/html, one capture per day (collapse=timestamp:8) — or per month for spans over 900 days. A new "version" starts whenever the content digest (SHA-1) changes.
• Capture selection: exact 14-digit timestamps if given, otherwise the successful HTML capture closest to each date, taken from the timeline query (from = before − 30 days, to = after + 30 days); only if that is empty does the tool fall back to CDX closest=…&sort=closest&limit=1.
• Archived pages are fetched raw (without the Wayback toolbar or URL rewriting) from https://web.archive.org/web/<timestamp>id_/<original URL>. Identical digests skip the fetch.
• The two versions are compared with the Website Change Explainer engine: block-level LCS diff, word diffs, and rule-based categories (price, legal/policy terms, contact, link target, title, date, heading, number) ranked above trivial noise (whitespace, timestamps, copyright years, tracking parameters).
• Similarity is the Dice coefficient over the words of the extracted page text (htmlToText).
• Caveats: digests also change for http/https/www variants, embedded tokens or ads; the archive may miss periods; content loaded by JavaScript after page load is usually not in the raw HTML.

Sources

• Wayback CDX Server API (Internet Archive)
• Wayback Machine (Internet Archive)