● Covered by 1 source · 1 reportLow impact1 neutral
Unicode Symbols Enable Domain Hacks Using Letter-Like Characters
Key points
- Unicode symbols like '℡' and '№' map to TLDs like '.tel' and '.no'.
- Browsers normalize these characters to ASCII using IDNA2008 (RFC5895).
- This functionality works across modern browsers and tools like wget/curl.
- Social media sites and DNS tools like dig/host do not support these URLs.
Unicode Characters in Domain Names
The Unicode standard includes various symbols that can be interpreted as domain name components. Specifically, letter-like symbols such as the Telephone symbol (℡) and the Numero Sign (№) correspond to existing Top-Level Domains (TLDs) like .tel and .no. This allows for domain names like 'https://edent.℡/' to resolve to 'https://edent.tel/'.
Browser Normalization Process
When a browser encounters these Unicode characters in a URL, it performs a normalization process. This process, defined by IDNA2008 (RFC5895), maps the Unicode symbol to its ASCII equivalent. For example, the '℡' symbol (U+2121) is mapped to 'TEL' based on its compatibility decomposition in the UnicodeData.txt file.
Widespread Browser Compatibility
This domain hack functions across modern web browsers and operating systems. Command-line tools such as `wget` and `curl` also successfully resolve these URLs. This indicates a broad implementation of IDNA2008 in common web clients.
Limitations and Incompatibilities
Despite broad browser support, these Unicode-based domain names have limitations. Social media platforms like Twitter and Facebook do not recognize them as valid URLs, preventing auto-linking. Additionally, some command-line DNS tools, such as `dig` and `host`, do not understand these characters and fail to resolve them.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
The daily brief
One email each morning: the day's tech stories, clustered across outlets and summarized. No account needed.
One email a day. Unsubscribe in one click, any time.
Today's brief
Spend a few minutes, get the whole day. Every topic's top stories in one hands-free rundown — listen, watch, or read the transcript.
▶ Play today's brief
New every morning, and the back catalogue is archived by date.
Reporting from
Certain Unicode symbols, such as '℡' and '№', can be used in domain names to resolve to their ASCII equivalents like '.tel' and '.no' due to browser normalization via IDNA2008. This allows for unusual domain representations that function in modern browsers and some command-line tools, though social media platforms and specific DNS tools may not recognize them.