What is an IDN homograph attack?

An IDN homograph attack registers a domain using Unicode characters that look identical to Latin letters · for example the Cyrillic 'а' (U+0430) in place of the Latin 'a'. The result, such as 'аpple.com', is visually indistinguishable from the real domain but resolves somewhere else, making it a powerful phishing technique.

Punycode is an encoding (RFC 3492) that represents Unicode domain labels using only ASCII. An internationalized label is encoded with an 'xn--' prefix, e.g. 'xn--80ak6aa92e.com'. Browsers display punycode when a label mixes scripts to help users spot spoofing.

How do I know a domain is suspicious?

Warning signs include non-ASCII characters mixed with Latin letters, multiple Unicode scripts in one label, characters from the Unicode confusables set, and an 'xn--' punycode form that decodes to a familiar-looking brand. This tool flags each of these.

Is the domain sent to a server?

No. Decoding and analysis run entirely in your browser. Nothing is uploaded.

Punycode & Homoglyph Detector

Paste a domain or URL to decode xn-- punycode, reveal deceptive Unicode lookalike characters and detect IDN homograph phishing. Everything runs in your browser.

Domain or URL

Examples:

Analysis

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How to use

Paste a domain

A bare domain, full URL or punycode label all work.

Review the verdict

Suspicious characters and mixed scripts are highlighted.

Compare forms

See both the Unicode and ASCII (punycode) representations.

Frequently Asked Questions

Registering a domain using Unicode characters that look like Latin letters · e.g. Cyrillic 'а' for Latin 'a'. The result is visually identical to a real brand but resolves elsewhere · a classic phishing technique.

An ASCII encoding (RFC 3492) for Unicode domain labels, prefixed with 'xn--'. Browsers show punycode for mixed-script labels to help users spot spoofing.

Watch for non-ASCII mixed with Latin, multiple scripts in one label, Unicode confusables, and 'xn--' forms that decode to familiar brands. This tool flags each.

No. Everything runs in your browser.

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