URL character limitations and encoding standards require domain names to follow strict ICANN and IETF rules while allowing the URL path more flexibility through UTF-8 and percent-encoding. This technical divide means that while you can include emojis in a URL path, the domain name portion remains restricted by legacy system requirements. The URL structure suits technical SEO specialists and brand owners, while PPC specialists can skip it.
Who should act on URL character limits and who should skip it
Readers who should act on URL character limits and encoding standards
- Technical SEO specialists should learn the distinction between Punycode and percent-encoding to ensure site architecture remains compliant with global standards.
- Content marketers should understand how emojis and non-English characters are processed to manage user expectations across different browsers.
- Web developers should implement hyphens as word separators to ensure search engines and humans interpret URL paths correctly.
- Brand owners should consult Punycode requirements before attempting to use non-English characters in a primary domain name.
Readers who should skip URL character limits and encoding standards
- PPC specialists should skip this analysis and instead consult the official Google Ads documentation for campaign-specific URL rules.
- Social media managers should focus on platform-specific link previews rather than technical character encoding.
What to do next about URL character limits and encoding standards
- Replace all underscores with hyphens in URL paths to ensure Google treats words as separate entities.
- Verify Internationalized Domain Name (IDN) translations by checking for the xn-- prefix in your domain records.
- Test emoji path rendering in social media previews to ensure the string does not appear as gibberish to human users.
Domain name standards are governed by ICANN and IETF
Domain name standards are governed by ICANN and IETF to ensure the internet’s address book remains functional and predictable. These organizations use RFC 1035 and RFC 1123 to define the specific characters, such as A-Z letters and hyphens, that the domain portion of a URL can contain. Google follows these same standards to ensure that any website it crawls adheres to the official standard web infrastructure.
If you attempt to create a domain that deviates from these rules, the registration will fail before it ever reaches a search engine. The domain part must be technically valid for the entire internet before SEO factors are even considered.
How Internationalized Domain Names (IDNs) work via Punycode
Internationalized Domain Names (IDNs) allow users to include non-English character sets, such as Chinese or Arabic, in their domain names. Computers process these characters by transforming them into Punycode, a text string that starts with the xn-- prefix. This system ensures that the domain remains compatible with legacy systems while appearing as native characters to the end user.
What is Punycode?
Punycode is a translation method that converts non-ASCII characters into a compatible ASCII string starting with xn--. It allows the internet to support diverse languages while maintaining the technical integrity of the DNS system. Using Punycode ensures that your domain remains reachable by all browsers and devices.
Why emojis are not allowed in domain names
Emoji characters are not allowed in domain names because current ICANN and IETF standards do not support them in the domain string. Even though an emoji might be converted into a Punycode string, the official standards for domain names explicitly forbid them. Using emojis in a domain name would result in a failed registration or a domain that humans cannot easily spell or find.
URL path flexibility and UTF-8 character support
URL paths offer significantly more freedom than domain names because they are governed by RFC 66 and support UTF-8 characters. You can include emojis, special characters like exclamation marks, or non-English text in the part of the URL that follows the TLD. Googlebot can crawl and process these characters as long as the underlying server supports the encoding.
The technical difference between Punycode and Percent-encoding
The technical difference between Punycode and Percent-encoding lies in where they are applied within the URL structure. Punycode is used for the front end of the URL (the domain) to satisfy domain name server requirements. Percent-encoding is used for the back end (the path) to allow web servers to handle a wider variety of characters.
What is Percent-encoding?
Percent-encoding is a method of translating UTF-8 characters into a string of percent signs and hexadecimals, such as %f0. It allows browsers and servers to handle special characters and emojis by representing them as a string of standard characters. This ensures that complex symbols can travel through the URL without breaking the connection.
Think of the domain as a physical street address that must be written in a specific format for the post office, while the path is like a room number that can have a much more creative design. The domain must be strictly compatible with the internet’s “address book” architecture. The path is where the web server takes over the responsibility of interpreting your specific content.
Why hyphens are superior to underscores for URL structure
Hyphens are the universal word separator across the web and are recommended by Google for structuring URL paths. Google treats the words linked together with underscores as one long word rather than two distinct terms. Using underscores can lead to confusion in how search systems parse your keywords.
Choosing a hyphen ensures that both humans and search systems can quickly identify the individual words in a link. For example, using “chicken-gear” clearly separates the concepts, whereas “chicken_gear” might be interpreted as a single, unique term. Use hyphens to maximize readability and ensure your URLs are built for humans first.
Prioritizing human readability over keyword stuffing
Prioritizing human readability over keyword stuffing is the primary goal for modern URL structure. While the technology allows you to include complex strings, doing so can result in URLs that look like gibberish in browser address bars or social media previews. A clean, descriptive URL builds user trust and prevents your link from appearing as a technical error.
Keyword stuffing in the URL provides an incredibly small signal that only matters if the site has zero content. Once a page has actual text and headers, the presence of keywords in the URL becomes basically irrelevant for ranking. Keep your URLs simple, descriptive, and easy to share to ensure they remain useful for your audience.
A marketer’s decision on emoji usage
Suppose a marketer wants to create a URL for a “Best Grilled Chicken” page and wants to include a chicken emoji. They first check the domain requirements and find that the emoji is not allowed in the domain name due to ICANN standards. They then move to the URL path and include the emoji, which the system automatically converts to a percent-encoded string like %f0. While the link is technically crawlable, the marketer ultimately decides to stick to words to ensure the link doesn’t look like gibberish when shared on social media.
If the marketer had tried to put the emoji in the domain instead of the path, the registration would have failed immediately because of the strict RFC 1035 and 1123 rules.
Social media platforms and browsers have not confirmed UTF-8 character and percent-encoded emoji rendering
- Various social media platforms have not announced exactly how they will render every possible UTF-8 character in link previews.
- Specific browsers have not confirmed how every percent-encoded emoji will appear in their address bars.
Frequently Asked Questions
Can I put a chicken emoji in my domain name?
You cannot put a chicken emoji in a domain name because ICANN and IETF standards do not support emojis in the domain part of a URL. While the emoji would be converted to Punycode, the underlying rules for domain names forbid it to ensure global compatibility.
Do keywords in the URL help with ranking?
Keywords in the URL provide an incredibly small ranking signal that only matters if the site has zero content. Once you add content to the page, the keywords in the URL become basically irrelevant for how Google ranks the page.
What is the difference between a hyphen and an underscore in a URL?
The difference between a hyphen and an underscore is that Google treats words linked by underscores as one long word. Hyphens are the universal word separator and are recommended because they improve readability for both search systems and human users.
Source: What can you actually put in a URL 🐔? (Google Search Central).