URL / メール / ドメイン バリデーター

URL / Email / Domain Validator - Check Inputs Online

URLs, email addresses, and domains follow strict syntax to avoid ambiguity on the web. This page validates them quickly using the browser’s URL constructor and reliable patterns.

What is being validated?

For URLs, we rely on the WHATWG URL standard via the browser constructor, normalizing input and assuming http:// when a scheme is missing for convenience. Email and domain checks use pragmatic patterns that cover common cases without attempting full DNS or MX lookups.

How it works

Paste a value and choose URL, Email, or Domain. The tool reports whether the input is valid and, for URLs, shows a normalized form. All checks run locally in your browser—no data is sent to a server.

About this validator

Pattern‑based validation is best for quick checks. Production systems should perform server‑side validation and may include DNS queries or allowlists/denylists tailored to your needs.

Use fast local checks during development, and add authoritative validation on the server before persisting or trusting user input.