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I'm the creator of https://T.LY https://T.LY URL Shortener and am always interested when I see new short link services. My biggest piece of advice is to figure

I'm the creator of https://T.LY https://T.LY URL Shortener and am always interested when I see new short link services. My biggest piece of advice is to figure out a way to detect malicious URLs before your service is completely shut down. A month after starting T.LY, my servers were disabled by my hosting company without warning. Since then, I've worked on systems and tools to prevent malicious short links and make the service more reliable. Most comments I see here are questioning why we still need URL shorteners. Print, media, SMS, and analytics are just a few reasons. I wrote some additional info on my blog: https://timleland.com/are-url-shorteners-useful-today/ https://timleland.com/are-url-shorteners-useful-today/ Another interesting thought is when you create a TinyURL, it's 20 characters long, and Bitly links are 14 characters long. These services cannot create short links anymore. As a URL shortener grows, the number of actual short links diminishes. Currently, T.LY has over 10 million short links, which means plenty of four and five-character short URLs are available. Two character URLs 3,844 (62^2) unique combinations Three character URLs 238,328 (62^3) unique combinations Four character URLs 14,776,336 (62^4) unique combinations Five character URLs 916,132,832 (62^5) unique combinations Six character URLs 56,800,235,584 (62^6) unique combinations Seven character URLs 3,521,614,606,208 (62^7) unique combinations Eight character URLs 218,340,105,584,896 (62^8) unique combinations

lioeters 4y ago
Just curious, can a short link be a single emoji as the URL (after domain)? If so, does it technically take up 4 characters? And (if you don't mind answering) how much does such a short domain like t.ly cost?
- jraph 4y ago
  It is possible, but your users will need to type emojis (which can be hard or impossible on some devices), or you'll need to urlencode it in href attributes and it will actually take encodeURIComponent("").length = 12 characters (imagine a simple emoji between the quotes). It will also require bigger QRCodes than alphanumeric characters. It might display incorrectly in address bars.
  - steventey 4y ago
    Yeah, someone actually created an issue for this on the repo: https://github.com/steven-tey/dub/issues/8 https://github.com/steven-tey/dub/issues/8 I'm planning to not allow emojis simply because of the accessibility challenges that it presents to users :') Emoji domains though, on the other hand, are really cool and more than welcome to be added :)
steventey 4y ago
Hey Tim! Thanks a lot for sharing your experience with T.LY! I'm definitely going to implement some abuse prevention measures over the next few days. My first instinct is to prevent folks from pointing shortlinks to certain malicious sites – do you think that'll be enough? Or are there other abuse vectors? Also, very interesting note regarding the hash combinations! The main focus of Dub is probably going to be for folks to add their own domains – but this is something that I'll keep in mind as well!

lioeters 4y ago

Just curious, can a short link be a single emoji as the URL (after domain)? If so, does it technically take up 4 characters? And (if you don't mind answering) how much does such a short domain like t.ly cost?

jraph 4y ago
It is possible, but your users will need to type emojis (which can be hard or impossible on some devices), or you'll need to urlencode it in href attributes and it will actually take encodeURIComponent("").length = 12 characters (imagine a simple emoji between the quotes). It will also require bigger QRCodes than alphanumeric characters. It might display incorrectly in address bars.
- steventey 4y ago
  Yeah, someone actually created an issue for this on the repo: https://github.com/steven-tey/dub/issues/8 https://github.com/steven-tey/dub/issues/8 I'm planning to not allow emojis simply because of the accessibility challenges that it presents to users :') Emoji domains though, on the other hand, are really cool and more than welcome to be added :)

steventey 4y ago

Hey Tim! Thanks a lot for sharing your experience with T.LY! I'm definitely going to implement some abuse prevention measures over the next few days. My first instinct is to prevent folks from pointing shortlinks to certain malicious sites – do you think that'll be enough? Or are there other abuse vectors? Also, very interesting note regarding the hash combinations! The main focus of Dub is probably going to be for folks to add their own domains – but this is something that I'll keep in mind as well!