Bulk Domain Cleaner

Paste a messy list of links and get back one clean domain per line. This free cleaner strips protocols, www., paths, query strings and ports, collapses subdomains to root domains, merges duplicates and reports the lines it could not use. Everything runs in your browser, so your list is never uploaded or stored.

What is a bulk domain cleaner?

A bulk domain cleaner takes a messy, multi-line list of links, hostnames or email addresses and returns the same list reduced to clean root domains, with duplicates removed. Instead of editing hundreds of rows by hand, you paste once and copy a normalised list back out.

It is a formatting tool, not a scraper or a data provider. It never visits the links, never expands a shortener, and never checks whether a site exists or is a business. It only removes the parts of a URL that are not the domain and merges entries that resolve to the same domain.

How to use the bulk domain cleaner

1. Paste your list into the Domains, URLs or emails box. One entry per line is easiest, but tab-, comma- and semicolon-separated values are split automatically, so a spreadsheet column or a CSV row works too.
2. Leave Remove www. and Collapse to root domain switched on unless you specifically need subdomains kept separate.
3. Turn on Sort A→Z if you want an alphabetical list for a spreadsheet import.
4. Read the Result panel: the ring shows how many unique domains you have, and the tiles show entries read, duplicates merged and unusable lines.
5. Check the Review panel for anything that was skipped, then copy the Cleaned list.

What the cleaner removes from each entry

Part of the URL	Example input	After cleaning
Protocol or scheme	https://example.com	example.com
www. prefix	www.example.com	example.com
Path, folder or file	example.com/pricing/plans	example.com
Query string	example.com?utm_source=li	example.com
Fragment or anchor	example.com#team	example.com
Port number	example.com:8080	example.com
User details before @	[email protected]	example.com
Subdomain (with the option on)	blog.eu.example.com	example.com
List markers and punctuation	“https://example.com”,	example.com
Defanged notation	hxxp://example[.]com	example.com

How deduplication works

Two entries are duplicates when they clean to the same string. Because the cleaner lowercases every host, strips a leading www. and (by default) reduces subdomains to the root domain, a set of different-looking links collapses to one line. In this list, all four entries are the same domain:

• https://www.Example.com/pricing?ref=newsletter
• http://blog.example.com/careers
• example.com
• EXAMPLE.com

They become a single output line, example.com, and the three extra entries are counted as merged duplicates. Turning Collapse to root domain off instead keeps blog.example.com as its own entry, which is useful when you do want subdomains separated.

Root domains and multi-part suffixes

Reducing a hostname to its registrable domain — the part you would actually register and email — needs a public suffix list, because suffixes such as co.uk and com.au contain two labels rather than one. This tool ships a compact list of the common second-level tokens (co, com, net, org, gov, edu, ac and similar) and, when the country code is two letters and the second-to-last label is one of those tokens, keeps the last three labels. So shop.acme.co.uk becomes acme.co.uk rather than co.uk.

That rule covers the overwhelming majority of everyday domains but is not the full Public Suffix List. Unusual suffixes, private suffixes and newer multi-part endings can be reduced one label too far. If a domain in your list looks wrong, turn Collapse to root domain off and clean the list again.

Worked example

Pasting the sample list that ships with the tool produces these numbers. They come from the algorithm described on this page, not from a benchmark.

Metric	Value
Entries read	11
Unique domains kept	5
Duplicate entries merged	4
Unusable entries skipped	2
Output	example.com, acme.co.uk, beta.io, gamma.dev, example.org

The two skipped lines are an IP address (192.168.0.1) and the plain phrase not a domain. Neither has a registrable domain, so both are reported in the skipped list rather than guessed at.

What gets skipped, and why

Reported reason	Example	Why
Missing a top-level domain	intranet	A single label with no dot is not a registrable domain.
IP address, not a domain	10.0.0.7	IPs have no registrable domain or subdomain structure to collapse.
Not a valid domain name	example..com	Empty labels and characters outside letters, digits and hyphens are rejected.
Longer than 253 characters	—	253 characters is the DNS hostname limit.

Limitations

• The output is a string transformation. The cleaner never contacts the domains, so it cannot tell you whether a domain is live, parked, a business or a competitor.
• Root-domain collapsing is a heuristic list of suffix tokens, not the complete Public Suffix List. See “Root domains and multi-part suffixes” above.
• It works on entries that are a link, hostname or email address. To pull domains out of free-form sentences or a full HTML page, clean those files first, because prose is left untouched.
• Commas and semicolons are treated as separators, so a URL that legitimately contains a comma in its path is split at that comma. Paths are discarded anyway, so the domain is unaffected.
• Unicode (internationalised) domains are matched only in their ASCII or punycode form, for example xn--bcher-kva.example. Branded Unicode text is not converted.
• It deduplicates exact domains after normalisation. It does not treat related brands, subsidiaries or a company and its parent as the same entity.

Frequently asked questions

Does the cleaner prove that a domain is real?

No. It reformats text. A domain that is live and a domain that was mistyped clean exactly the same way, and both appear in the output. Verification needs a separate step.

Why did two of my links merge into one line?

Because they reduce to the same root domain. A marketing page, a careers subdomain and the bare domain all become one entry when Collapse to root domain and Remove www. are on. Switch off collapsing to keep subdomains apart.

Should I keep the www. or the root domain?

For prospecting and CRM imports, the root domain is usually the safer key, because it is stable across a website redesign. If your pipeline needs a specific subdomain — for example a hosted help centre on its own hostname — turn collapsing off.

Can it remove duplicates without changing the domains?

Yes. Turn Collapse to root domain and Remove www. off and the tool only strips protocols and paths, lowercases, and merges exact repeats. The cleaned entries keep the hostname you pasted.

Is my list uploaded anywhere?

No. The tool is pure HTML, CSS and JavaScript running in your browser. There is no server request, no account, no cookie and no local storage, so nothing you paste leaves the page.

How many domains can it handle at once?

There is no fixed limit, but the results are recalculated on every keystroke after a short pause. Very large lists of tens of thousands of lines will still work, yet the browser will feel slower while you type. Paste, then let it settle before copying.

Does it sort the list?

Only if you switch on Sort A→Z. By default the cleaned list keeps the order of first appearance, so the most prominent domain in your source stays at the top.

Related tools

• Company name to domain finder — guess a domain when you only have a company name
• Business email permutator — turn a clean domain into first.last address patterns
• Email pattern detector — infer a company’s address pattern from a few samples
• Lead list deduplicator — merge whole CSV rows on email or domain

Next step

Cleaning the list is the first hour of the work; turning it into meetings is the rest. That is what mizanursguide.com helps with. See how we build B2B lead generation systems that start from a clean list and end with booked calls.