{"id":3419,"date":"2026-07-05T22:15:21","date_gmt":"2026-07-05T22:15:21","guid":{"rendered":"https:\/\/exponentialdecay.co.uk\/blog\/?p=3419"},"modified":"2026-07-07T10:27:16","modified_gmt":"2026-07-07T10:27:16","slug":"shortened-links-expand-them-and-save-the-urls","status":"publish","type":"post","link":"https:\/\/exponentialdecay.co.uk\/blog\/shortened-links-expand-them-and-save-the-urls\/","title":{"rendered":"Shortened links? Expand them and save the URLs"},"content":{"rendered":"

Shortened links are a digital preservation and web archiving nightmare. You can imagine how they need to work:<\/p>\n

    \n
  1. Create a unique short code for a given (target) URL (like a hash, but far far shorter)<\/li>\n
  2. Pair the short code with your URL in a database.<\/li>\n
  3. Create a redirect rule on the URL shortening server from the new source URL to the target URL.<\/li>\n
  4. Send the shortened link to the caller, e.g. shortURL.com\/123badf00d<\/code><\/li>\n
  5. In-perpetuity:<\/em> continue to pay for your domain; maintain the database; look after redirect rules during server migrations; ensure duplicate short-codes are not created.<\/li>\n<\/ol>\n

    A URL-shortening business in five easy steps.<\/p>\n

    But what does that mean for digital preservation?<\/p>\n

    <\/p>\n

    URL shortening and digital preservation<\/h2>\n

    There are different degrees of issue with URL shortening.<\/p>\n

      \n
    1. The reality is that databases of redirects are not maintained and links disappear.<\/li>\n
    2. Shortened links obfuscate meaning and may be harmful.<\/li>\n<\/ol>\n

      The problem of (2) can happen with regular hyperlinks, especially with domain squatting, but domain squatting aside, there’s usually some authority, and thus provenance, associated with a domain name and its top-level-domain, e.g. you should usually be fine with .gov .edu<\/code> and so on.<\/p>\n

      NB.<\/strong> I don’t have numbers on skew. Skew is usually the phenomenon of content changing behind a hyperlink after it was first published, but with short URLs, skew might mean pointing to two different domains over time. I have only seen something similar with QR codes that used an additional proxy in between the redirect to enable the target URL to be updated and replaced multiple times<\/a>; but this is not a dissimilar mechanism from a URL shortening service.<\/em><\/p>\n

      Can I get more information?<\/h2>\n

      Take a bit.ly URL that works today… bit.ly\/2lfnTqv<\/code><\/p>\n

      Use cURL to get the header information with the -I flag<\/a>: curl -I bit.ly\/2lfnTqv<\/code><\/p>\n

      HTTP\/1.1 301 Moved Permanently<\/strong>\r\nServer: nginx\r\nDate: Thu, 02 Jul 2026 17:47:26 GMT\r\nContent-Type: text\/html; charset=utf-8\r\nContent-Length: 130\r\nCache-Control: private, max-age=90\r\nContent-Security-Policy: referrer always;\r\nLocation: http:\/\/choosestainless.outokumpu.com\/case-barbarastollen-underground-archive\/<\/strong>\r\nReferrer-Policy: unsafe-url\r\nSet-Cookie: _bit=q62hLq-038ddea2565856aace-00S; Domain=bit.ly; Expires=Tue, 29 Dec 2026 17:47:26 GMT\r\nX-Robots-Tag: noindex\r\nVia: 1.1 google\r\n<\/pre>\n
      I have highlighted three key pieces of information that we really need to pay attention to:<\/p>\n