YUCTS Tools

Suspicious URL Structure Checker (@, IP, Punycode, short links)

Paste a URL to list structural features such as “@” tricks, numeric IP hosts, Punycode and mixed scripts, URL shorteners and double extensions. It never opens the link and gives no safety verdict.

  • Runs in your browser with cited reference data

Paste a link. The URL is never opened or fetched; only the structure of its text is inspected.

Try an example

This tool only inspects how the URL is written. It cannot tell whether a site is safe or a scam, and finding no features does not mean the link is safe.

Analysis

Structural features (5)

Host the browser would connect to

xn--exmple-4nf.com

Displayed as: exаmple.com

Structural features (5)

  • Strong cautionText before “@” (user info)

    Everything before “@” is treated as a user name, not as the site. The browser connects to the host after “@”, so a familiar name in front of “@” can be misleading.

    Found: secure.example.com@xn--exmple-4nf.com

  • Strong cautionLetters that imitate Latin letters

    The host uses characters from other scripts that look like Latin letters. It can be read as “example.com”, but it is a different address.

    Found: exаmple.com

  • Strong cautionSeveral scripts in one label

    The label “exаmple” combines Latin + Cyrillic. Unicode TR #39 restriction level: Minimally Restrictive (for example Latin mixed with Cyrillic or Greek).

    Found: exаmple

  • CautionInternationalized domain name (Punycode “xn--”)

    The domain contains non-ASCII characters, written as “xn--…”. Compare the decoded form carefully with the site you expect.

    Found: xn--exmple-4nf.com → exаmple.com

  • NoteAnother URL inside the link

    The path or a parameter contains a complete URL (1 found). Sites use this for redirects, which can also forward you to a different site.

    Found: next=https://example.net/

URL components

Scheme
https:
User info
secure.example.com
Host (as typed)
xn--exmple-4nf.com
Host (ASCII / Punycode)
xn--exmple-4nf.com
Host (Unicode)
exаmple.com
Port
not specified (default 443)
Path
/login
Query
next=https://example.net/
Fragment (#)
none

How to use

  1. Copy the address of the link you are unsure about and paste it into the field — there is no need to open it.
  2. Check “Host the browser would connect to” to see where the link really points.
  3. Read the listed features, and verify the sender another way, for example by opening the official site or app yourself.

FAQ

Does this tool tell me whether a site is safe?

No. It only lists features of how the URL is written; it does not judge safety, scams or malware. A URL without any features can still be dangerous, and one with features can be legitimate. When in doubt, do not open the link — go to the official site or app yourself.

Is the URL sent anywhere?

No. Everything is analysed in your browser and the URL is never accessed. Nothing you enter is stored or logged, and it disappears when you close the page.

What is Punycode (xn--)?

It is the ASCII form of a domain name that contains non-ASCII characters (RFC 3492). The tool decodes labels starting with “xn--” so you can check whether look-alike characters are used.

Why is an “@” in the address worth attention?

In a URL such as “https://well-known-site@another-host/”, everything before “@” is a user name; the browser actually connects to the host after “@”. Check “Host the browser would connect to” instead of the first name you read.

What is a “label”?

Each part of a host name between dots. For example, “www.example.com” consists of the three labels “www”, “example” and “com”.

Notes & limitations

  • What you enter is processed only on this page and is not sent to YUCTS servers.
  • Only the structure of the URL text is inspected. The site’s content, reputation, blocklist status, scams or malware are not checked.
  • Script mixing follows the Unicode TR #39 (18.0.0) procedure using the browser’s Unicode data. Look-alike detection covers only a selected subset of characters from confusables.txt.
  • IDNA validation (for example bidirectional and joiner rules) is simplified, so some hosts that browsers refuse may still be analysed.
  • The shortener list contains 40 major domains checked on 2026-10-31 and does not cover every service.
  • The thresholds for many subdomains (5 or more labels) and long URLs (more than 200 characters) are rules of thumb.
  • The URL you enter is processed only on this page; it is never accessed, stored, logged or sent.

Data sources