URL Validator
Check whether a URL is correctly formatted.
This tool runs entirely in your browser. Your files are never uploaded to a server.
What this tool does
Checks whether a single URL is syntactically well-formed, using the browser's own URL parser, and reports one of three outcomes: valid, missing a protocol, or containing stray spaces.
How to use it
Type or paste a URL into the field. The result updates on every keystroke, showing a green valid message or a red invalid message with the specific reason as soon as you stop typing.
Worked example
https://example.com/path?query=1 is reported valid. example.com/path (no scheme) is reported invalid with a missing-protocol reason, and https://example .com (a stray space before .com) is reported invalid with a contains-spaces reason.
What counts as invalid
Three checks run in order: the text is trimmed first, then checked for any remaining internal space, then checked for a leading scheme matching a pattern like https:// or ftp://, and finally handed to the browser's URL constructor — any of these three steps failing marks the input invalid, with a matching reason.
What it doesn't check
This is a format check only. It never makes a network request, so a URL that is perfectly well-formed but points to a domain that doesn't exist, isn't reachable, or returns a 404 will still be reported as valid.
Limitations
Leading and trailing spaces are trimmed before checking, so they never trigger the space warning — only a space in the middle of the URL does. Relative paths and protocol-relative URLs (like //example.com) are always reported invalid, since they have no explicit scheme for the URL constructor to resolve.
Privacy and processing
Validation runs entirely client-side using the browser's built-in URL API. The address you type is never sent anywhere or requested.
Frequently Asked Questions
- Does this check if the URL is live or reachable?
- No, this checks format only, using the browser's URL API. It does not make any network request, so a correctly formatted but dead or nonexistent URL will still pass.
- What kinds of errors does it catch?
- It flags a missing protocol (like forgetting https://), stray spaces in the URL, and generally malformed structures that the URL API rejects.
- Why does a URL without https:// fail?
- An absolute URL needs a protocol so the browser knows how to interpret it — without one, the URL API can't parse the string and marks it invalid.