Clean a list before import
Spot addresses missing https:// or badly copied before importing them into an email tool, a CMS or a spreadsheet.
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Result
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How does this tool work?
This validator checks a list of URLs, one per line, with the browser’s own URL parser, the same one web pages use. For each valid address it shows the normalised form and breaks it down into protocol, host and path; lines that do not form an absolute URL are marked with a cross.
Each non-empty line is parsed separately according to the WHATWG URL Standard, which every modern browser implements; leading and trailing spaces are ignored.
A valid URL is marked ✓ and rewritten in its normalised form: lower-case domain, non-ASCII characters in the path encoded as %XX, and a slash added after the domain if the path is empty.
The next line details protocol, host (with the port if one is given) and path. The path keeps its case: /Cafe and /cafe remain two different addresses.
A line that is not an absolute URL (no scheme, as in example.com/contact, or a space in the domain) is marked ✗ and shown as it was entered.
How to use this tool
Paste the URLs
One address per line in the Input field.
Run the check
Click Process.
Read the result
✓ for a valid URL with its breakdown, ✗ for a rejected line.
Fix the rejected lines
Add the missing scheme, remove spaces or encode forbidden characters, then run it again.
Use cases
Check generated links
Review URLs produced by a script or spreadsheet formula before publishing them.
Understand normalisation
See how the browser rewrites an address with capitals or accents, and why two URLs that look the same differ.
Examples
Four lines, two rejected
The domain is lower-cased and the é in the path is encoded; example.com/contact is rejected for lack of a scheme; mailto: is a valid scheme with no host; the space in the domain makes the last line invalid.
Input
Input:
https://Example.com/Café?q=1
example.com/contact
mailto:hello@example.com
https://exa mple.com
ProcessResult
Result:
✓ https://example.com/Caf%C3%A9?q=1
protocol=https: host=example.com path=/Caf%C3%A9
✗ example.com/contact
✓ mailto:hello@example.com
protocol=mailto: host= path=hello@example.com
✗ https://exa mple.comTips and best practices
- Valid does not mean reachable: the tool checks syntax, not whether the domain exists or the server responds.
- Every scheme is accepted (mailto:, tel:, ftp:, javascript:): check the protocol if you only expect https web links.
- An internationalised domain is converted to punycode: café.fr becomes xn--caf-dma.fr in the normalised form.
- To remove duplicates from a list, compare the normalised forms rather than the text you entered.
Sources and references
- RFC 3986 — Uniform Resource Identifier (URI): Generic Syntax (opens in a new tab), RFC EditorPage in English
Frequently asked questions
Why is example.com rejected?
Because an absolute URL must start with a scheme such as https://. Without it, example.com/contact is just a relative path. Add https:// in front.
Why does the displayed URL differ from what I entered?
The browser normalises it: lower-case domain, non-ASCII path characters encoded, default port removed (:443 for https). That is the form it will actually use for the request.
Does the tool check that the page exists?
No. It makes no network request; it only checks that the string forms a valid URL.
Are spaces always forbidden?
In the domain, yes. In the path or query, the browser encodes them as %20 and the URL stays valid.
Are my URLs sent to a server?
No. The check runs in your browser.
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