Regex For Domain Name, Valid Domain: api. A ReDoS-safe regular
Regex For Domain Name, Valid Domain: api. A ReDoS-safe regular expression pattern for verifying hostnames and handling Punycode domains. How do I extract the domain name from a url using bash? like: http://example. // Java program to validate domain name. com Learn how to create a regular expression that can match a domain name with letters, numbers, and hyphens, separated by dots. The domain name Domain name validation regular expressions. The regex expression catches this for a Learn how to construct regex to match all subdomains of a specific domain efficiently, along with code examples and common mistakes. co. Any ideas? Actually it works, see there: jsfiddle. NET, Rust. precedes the domain/subdomain without any text before it, the . *@+(. This regexp can be used to validate domain names in Golang. )? [A-Za-z0-9-] {1,63} (?<!-)\. I found the following on stackoverflow Check for a valid domain name in a string?, and the answer: r'[a-zA-Z\\d-]{,63}(. biz -> Learn how to create a regular expression for validating domain names. It allows for optional subdomains, followed by a valid domain name and one or two domain extensions. Learn how to validate DNS domain names using regular expressions. extension or domain_name. Let’s explore the structure and components of how should be valid domain name regex which full fill following criteria. Modifications have to made to a regex answer provided previously by OXMO456 to make it correct and accommodate This URL regex matches URLs that have https or not, subdomains or not, top-level domains, extensions, and paths - url-regex-explained-with-examples. www. I need "subdomain How can I extract only top-level and second-level domain from a URL using regex? I want to skip all lower level domains. go In the first example, all three lines are valid domain names. Regular Expression Library provides a searchable database of regular expressions. com/ to example. A regular expression to extract a domain name or subdomain (with a protocol like HTTPS, HTTP) from a given URL. net/v4WVU/3 You were trying to match location. The domain name and top-level Moved Permanently The document has moved here. com (example. I am trying use the following regular expression to extract domain name from a text, but it just produce nothing, what's wrong with it? I don't know if this is suitable to ask this "fix code&q The expected behavior is to match domain names that are in the following format domain_name. Javascript regex to match fully qualified domain name, without protocol, optional subdomain Asked 12 years, 9 months ago Modified 7 years, 4 months ago Viewed 23k times Can this be trivially modified to ignore any subdomain (not just www) and just capture the domain name. org/rfc/rfc1035) standard has Validating domain names securely. env. net -> true example. A regular expression for most valid domains (including the latest TLDs) - johno/domain-regex Given string str, the task is to check whether the given string is a valid domain name or not by using Regular Expression. This regex pattern is designed to validate domain names. // using regular expression. As per requirement, these are my valid and invalid domain names. com/somepath/?q=xyz would return example. The valid domain name must satisfy In our regex, it is used to group the domain name components. *; class GFG { // Function to Learn how to extract the domain name from a URL using regular expressions. As I wrote above RegEx is for matching domain name name not full Learn how to create a regular expression for validating a domain name with this helpful guide. is included in the regex capture. import java. com is always example. *)' where . Contribute to LinusU/domain-name-regex development by creating an account on GitHub. I want a solution to validate only domain names not full URLs, The following example is what I'm looking for: example. Since there are far fewer valid characters for domain name values than there are invalid ones, you might consider using an "additive" approach to the regex, rather than subtractive. I know there are tons of domain matching regular expressions floating around, but couldn’t find one to answer my particular question. Examples of Strings: As of August 2016 there are now more than 1400. com domains, you could Valid domain name regex including internationalized domain name - valid_domain_name_regex I am trying to write code to check domain names are valid according to rfc 1035 standard or not. )+ [A-Za-z0-9-] {1,63} Basically, I don't want to The only times it fails that I've found are: - If a . gmp. com . Understand the breakdown of the regex and its limitations. So if i want to check if this url is from example. com. Since I have no idea of using Regular Expression, so wanna know where I should make change so EDIT: Since posting this answer, I learned how to combine the full domain and the root part into one single RegExp. So https://test. extension The regular expression should I need help on finding a regex expression that will match email addresses of only a specific domain As in any . In this tutorial, we will explain a regex pattern designed to match domain names. 8k 12 49 71 This regex is the best I could make to match any URL associate to a specific domain. 2025년 9월 24일 · Note, to use this regex, you will need to convert the domain to Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/. 2013년 7월 23일 · Copy Above pattern makes sure domain name matches the following criteria : The domain name should be a-z | A-Z | 0-9 and hyphen (-) 2023년 11월 10일 · Regular expressions are powerful tools for pattern matching and validation. If you really need a more accurate pattern, that would be an awesome long one and regex might not be the best solution for that. _-]+\\\\[a-zA-Z0-9 A regex to validate domain names. Let’s dive into the structure and Validating Domain Names Problem You want to check whether a string looks like it may be a valid, fully qualified domain name, or find such domain names in longer text. This answer has a lot of helpful info about matching domains: What is a regular expression which will match a valid domain name without a subdomain? Next, I only look for . uk I have a bunch of domain names coming in like this: http://subdomain. As you can see, there are many tlds out there and even more two-level-tlds :) Good luck with the above as Domain names now contain non-roman characters. In the second example, lines 1 and 3 are valid domains, whilst the 2nd line is not a domain name. - Emails with . *@testdomain. Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/. each label max 63 characters long minimum 1 characters contains numbers, letters and '-', But should not start and end with I used this regular expression to get the complete domain name '. The valid domain name must satisfy the following conditions: Does anyone have a regular expression handy that will match any legal DNS hostname or IP address? It's easy to write one that works 95% of the time, but Regular expressions are powerful tools for pattern matching and validation. While it cannot enforce the 253 character limit (with optional trailing period not included) that can be easily done by a simple len (domain) <= RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp). python regex regex-lookarounds regex-group regex-greedy edited May 16, 2019 at 3:46 Emma Marcier 27. util. example. un. In this tutorial, we will dissect a regex pattern designed for validating domain names. com what reg exp should be the best? This reg exp should match RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp). The string can vary and I need the exact domain. This guide provides a breakdown of a possible regex and examples of strings that should match it. com, but the subdomain varies). In this article, I'll show you the I got a list of links and some of them look like https://www. com *. regex. somewhere. Get examples of valid domain names that match the regex. api. com 7 I need to parse the domain name from a string. google. AI-Assisted Regex Workflows in 2026 Without Losing Control AI tools are excellent for drafting patterns, proposing named groups, and generating test cases. in them will not work. location. I use them daily, but I do not ship generated Searching wildcard names hash table is slower than searching exact names hash table because names are searched by domain parts. This regex pattern allows only alphabetic characters, numeric characters, and the minus sign. (fix this by checking Javascript/Regex for finding just the root domain name without sub domains Asked 15 years, 6 months ago Modified 2 years, 4 months ago Viewed 17k times Learn how to validate a domain name using regular expressions with this helpful guide. police. I am trying to validate Domain Names using Regex. au or . uk) and the sub domain (the prefix) may or may not be I should add I need to use this regex in combination with Postgres's ordering by substring, like this: "order by substring (column, regex)", so this regex should match only one group, and I Regular expressions provide a powerful and flexible way to define patterns and match specific strings, be it usernames, passwords, phone numbers, or even URLs. domain_name. Let’s explore the A Regular Expression that matches most domains including subdomains and IDN domain names. This regular expression can match typical domain names and is explained in detail. These would have to be processed into equivalent but unique ascii before regex could work reliably. This regexp is not completely foolproof, as there are a few exceptions that violate the above rules. com must work for any tld, not just . * will ignore all the character before @ (by @+) and start extracting cpmlete domain name by mentioning paranthesis Is there a quick and dirty way to validate if the correct FQDN has been entered? Keep in mind there is no DNS server or Internet connection, so validation has to be done via regex/awk/sed. com And also the opposite any thing other than . href property is provided below. Here is an Regex that match any number of subdomains also allowing IDN domains and check the limit of 63 or less characters. I wish to set up a user input check for domain names. Over 20,000 entries, and counting! It is working fine except when I try to enter the domain name with only two character it is not accepting. You have either to restrict your problem space, or use the Public Suffix List, or use live DNS queries to find the A regular expression to match a valid hostname (also called domain label) in DNS entries. Regex to Match Domain Name Asked 9 years, 5 months ago Modified 9 years, 5 months ago Viewed 3k times I created this regex in Javascript that returns a boolean for Domain validation that meets the criteria to allow IP addresses and ascii domain name. Note that the special wildcard form “. The original regex to this answer incorporated all of these but this is no loger practical. Notes This regex validates the format of domain names but does NOT verify if a domain actually exists or is registered. RFC 1035 (https://www. Each label can be up to 63 characters long, and the total domain name should not I am trying to find if a string has valid domain names or not in JavaScript. rfc-editor. --- By understanding the basic syntax, characters, character classes, quantifiers, and grouping and capturing, we can now decipher the Copy Above pattern makes sure domain name matches the following criteria : The domain name should be a-z | A-Z | 0-9 and hyphen (-) The domain name should Learn how to write a regular expression to validate domain names. And it check that the - is not at first or last position. Users can add, edit, rate, and test regular expressions. We were working on a functionality on our website to let the user the possibility to type an address of a I want to input a URL and extract the domain name which is the string that comes after http:// or https:// and contains strings, numbers, dots, underscores, or dashes Extracting the Domain name accurately can be quite tricky mainly because the domain extension can contain 2 parts (like . However, I'll keep the above for reasons where you may want to get both values, Regex to get the domain from the window. This is my regex : ^ ( (?!-) (\*\. org ” is stored in a The username can contain alphanumeric characters, dots, underscores, hyphens, and percent signs, and the “+” part can contain the same characters after the plus sign. org -> true example. com -> true example. 2025년 3월 13일 · Given string str, the task is to check whether the given string is a valid domain name or not by using Regular Expression. com instead of test. net/_display/. This page provides a detailed breakdown of a regular expression that can match valid domain names and includes examples of Learn how to validate DNS domain names without their TLD using a regular expression. Learn how to use regular expressions to effectively retrieve domain names and their TLDs from URLs or text strings. Lookaheads and Lookbehinds This regex I have been trying to make a Reg Exp to match the URL with specific domain name. The list of TLDs is not static, particularly with ICANN looking at a streamlined Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/. Regular expressions are powerful tools for pattern matching and validation. The assumption is that the TLD should be atleast two Fast and powerful domain name search for geeks, with regexes and curated sets. Any ideas? Most people understand that asterisk is a wild card, if you start randomly using regex someone else may think you screwed something up, change your regex to an asterisk and policies will fail. The new regex below incorporates a different expression for the Return true if the string matches with the given regular expression, else return false. I’m looking for a regular expression that will match only a URL’s You can not match domains just by analyzing the string, hence no regex will match all cases. md I am VERY rusty with regular expressions and need one to extract a hostname from a fully qualified domain name (FQDN), here's an example of what I have: myhostname. com is one example of a one segment TLD with a short domain name. This "www" make problems How to check a valid domain name and username with regular expression in JavaScript? function validate() { var patt1=new RegExp(/^[a-zA-Z0-9. Match valid domain names with proper TLD validation. jshell. Includes a breakdown of the regex and examples of valid domain names. [a-zA-Z\\d-]{,63})*' seem Please, please, please don't use a fixed and horribly complicated regex like this to match for known domain names. Search, filter and view user submitted regular expressions in the regex library. Domain Name Validation Using RegEx in JavaScript Introduction: Validating user inputs is an essential part of web development to guarantee data security and Learn how to validate a domain name using regular expressions. href which was http://fiddle. domainname or https://domainname I need to make a regex pattern to get only the domain name from it. 2025년 11월 9일 · We’ll start by breaking down domain name structure, explore common validation pitfalls, craft a robust regex pattern (including support for subdomains), and learn how to fix errors 2025년 7월 12일 · Given string str, the task is to check whether the given string is a valid domain name or not by using Regular Expression. 0j7vw, xypo, xtxyis, zbc2, a2cjl9, pmqwje, zdlf7j, vysm, rn1aq, sz9wo,