Data Source and Methodology
This tool validates URLs by attempting to parse them according to the official Internet Engineering Task Force (IETF) standard: RFC 3986: Uniform Resource Identifier (URI): Generic Syntax, published in January 2005. You can read the full specification here.
All validation logic is based strictly on the standards defined in this document, as implemented by the browser's native URL parsing engine. This ensures up-to-date and highly accurate syntax checking.
The Formula Explained
A URL is not a single block of text; it's a structured string composed of several distinct parts. The generic syntax, as defined by RFC 3986, can be represented as:
Square brackets [] indicate optional components. The authority itself is often broken down further into [ userinfo @ ] host [ : port ].
Glossary of Variables
- Scheme
- The protocol used to access the resource (e.g.,
https:,http:,ftp:,mailto:). It is mandatory for a string to be considered a full, valid URL by this tool and must be followed by a colon:. - Authority
- The part of the URL that identifies the server. It includes the Host (a domain name like
www.example.comor an IP address like192.168.0.1) and an optional Port (e.g.,:8080). - Path
- The specific location of the resource on the server, following the host (e.g.,
/path/to/page.html). If omitted, it defaults to/. - Query
- An optional string of data parameters, beginning with a
?. Parameters are typically key-value pairs separated by&(e.g.,?search=test&id=123). - Fragment
- An optional internal page reference, or "hash," that points to a specific part of the resource. It begins with a
#(e.g.,#section-2) and is processed by the browser, not sent to the server.
How It Works: A Step-by-Step Example
Let's validate the following URL: https://www.example.com:8080/search?user=test#results
- Input: The user enters the string into the calculator.
- Parsing: The tool passes the string to the browser's native
new URL()constructor, which follows RFC 3986 rules. - Validation: The parse succeeds without errors. The tool reports the URL as Valid.
- Component Breakdown: The tool then extracts each component from the parsed object and displays them in the results table:
| Component | Value |
|---|---|
| Scheme | https: |
| Hostname | www.example.com |
| Port | 8080 |
| Path | /search |
| Query | ?user=test |
| Fragment | #results |
Frequently Asked Questions (FAQ)
Why is 'www.example.com' reported as invalid?
This tool validates against the strict, absolute URL syntax. A string like www.example.com is just a hostname; it's missing the scheme (e.g., https:// or http://). Browsers often auto-complete this for users, but technically, it is not a valid, complete URL on its own.
Are spaces allowed in URLs?
No, spaces are not valid characters in a URL. They must be "percent-encoded" as %20. If you paste a URL with a space, this tool will correctly identify it as invalid syntax.
Does this tool check if a website is online or safe?
No. This is a syntax validator, not a status checker or a security scanner. It only checks if the text string is formatted correctly according to URL standards. It does not check if the server is online (404 errors) or if the content is malicious.
What's the difference between a URL, URI, and URN?
A URI (Uniform Resource Identifier) is the overarching concept. A URL (Uniform Resource Locator) is a *type* of URI that specifies *how to get* to a resource (e.g., https:// tells the browser *how*). A URN (Uniform Resource Name) is another type of URI that just *names* a resource uniquely (e.g., urn:isbn:0451450523). All URLs are URIs, but not all URIs are URLs. This tool specifically validates the URL syntax.
Why did my URL fail with a "TypeError"?
This is the standard error from the browser's parser. It typically means the syntax is fundamentally broken. The most common reasons are a missing or misspelled scheme (e.g., htps://), invalid characters in the host (like _ or !), or an improperly formatted port.
Tool developed by Ugo Candido. Content verified by the CalcDomain Editorial Board.
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