I want a solution to validate only domain names not full urls, The following example is what i'm looking for:
domain.com -> true
domain.net -> true
domain.org -> true
domain.biz -> true
domain.co.uk -> true
sub.domain.com -> true
domain.com/folder -> false
domµ*$ain.com -> false
If you want to find out if a domain name is validated, simply type the URL into the WHOIS database. The search results will also provide you with other crucial information such as who owns it, when it was registered and when it is due to expire.
To validate a RegExp just run it against null (no need to know the data you want to test against upfront). If it returns explicit false ( === false ), it's broken. Otherwise it's valid though it need not match anything.
What is RegEx Validation (Regular Expression)? RegEx validation is essentially a syntax check which makes it possible to see whether an email address is spelled correctly, has no spaces, commas, and all the @s, dots and domain extensions are in the right place.
The accepted answer is incomplete/wrong.
The regex pattern;
should NOT validate domains such as:-domain.com
, domain--.com
, -domain-.-.com
, domain.000
, etc...
should validate domains such as:schools.k12
, newTLD.clothing
, good.photography
, etc...
After some further research; below is the most correct, cross-language and compact pattern I could come up with:
^(?!\-)(?:(?:[a-zA-Z\d][a-zA-Z\d\-]{0,61})?[a-zA-Z\d]\.){1,126}(?!\d+)[a-zA-Z\d]{1,63}$
This pattern conforms with most* of the rules defined in the specs:
Note 1: The full domain length check is not included in the regex. It should be simply checked by native methods e.g. strlen(domain) <= 253
.
Note 2: This pattern works with most languages including PHP, Javascript, Python, etc...
See DEMO here (for JS, PHP, Python)
The regex above does not support IDNs.
There is no spec that says the extension (TLD) should be between 2 and 6 characters. It actually supports 63 characters. See the current TLD list here. Also, some networks do internally use custom/pseudo TLDs.
Registration authorities might impose some extra, specific rules which are not explicitly supported in this regex. For example, .CO.UK
and .ORG.UK
must have at least 3 characters, but less than 23, not including the extension. These kinds of rules are non-standard and subject to change. Do not implement them if you cannot maintain.
Regular Expressions are great but not the best effective, performant solution to every problem. So a native URL parser should be used instead, whenever possible. e.g. Python's urlparse()
method or PHP's parse_url()
method...
After all, this is just a format validation. A regex test does not confirm that a domain name is actually configured/exists! You should test the existence by making a request.
UPDATE (2019-12-21): Fixed leading hyphen with subdomains.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With