miji.be"What is the world's shortest URL?" seems simple but is surprisingly deep. URL length comprises protocol (https://), domain name, and path, so this article looks at how short each element can be. The theoretical shortest URL is something like `http://a.co` at just 11 characters (12 for https). But the shortest actually accessible URL is more complicated.
For shortest domain records: domain names consist of a second-level domain (SLD) plus top-level domain (TLD). The shortest SLD is 1 character, and single-character .com domains actually exist: `x.com` (used by X (formerly Twitter)), `z.com` (long held by Nissan, later sold), `q.com`. However, only three single-character .com domains, `x`, `z`, and `q`, are actually registered; the remaining single letters were reserved in the early 1990s and cannot be newly registered. These single-character .com domains are not something an ordinary person can acquire. `x.com` made headlines when Elon Musk used it for Twitter's 2023 rebrand, though he originally acquired it in 1999 for his online bank X.com (later PayPal).
TLD shortness also affects URL length. The shortest TLDs are 2-character country-code TLDs (ccTLDs): `.ai` (Anguilla), `.io` (British Indian Ocean Territory), `.ly` (Libya), `.to` (Tonga). These 2-character TLDs were originally assigned to their countries or regions, but because they evoke English words or abbreviations, they have been used by short URL services and tech companies. `.ly` is used by short URL services such as bit.ly, and `.io` is sometimes used by tech startups. These small nations and territories earn revenue from domain registration fees. Tuvalu (`.tv`) entrusted the operation of the `.tv` domain to an overseas company in the late 1990s, in a contract said to total about $50 million; the operator later changed, and in the IANA record (updated August 5, 2026) the technical contact is GoDaddy Registry.
The domain shortness competition among short URL services has interesting history. From TinyURL (tinyurl.com: 11 characters), domains shortened to bit.ly (6), goo.gl (6), ow.ly (5), and t.co (4). Twitter's `t.co` is a short domain even among major short URL services. Domain shortness offers practical benefits beyond character limits: memorability and verbal communicability. When reading URLs on radio or TV, a short domain makes the URL easier to convey.
As URL trivia: web pages can be accessed without URLs by entering an IP address in the browser. `http://142.250.196.110` reaches Google's server. IP addresses can even be entered as decimal integers: `http://2398798958`, interpreting the four IPv4 octets as a single 32-bit integer. Some browsers support this format, though it's sometimes exploited in phishing attacks for URL obfuscation. Pursuing the shortness of URLs leads to how the internet works.