Domain normalizer

Turns URLs, emails and LinkedIn links into clean root domains and handles, with a dedupe key for each row.

10 inputs, one per line

Runs in your browser. The list never leaves your device.

Ken matches every list you import on the root domain.

So the same company never gets two sequences from two exports.

What the domain normalizer does

It turns any website, URL or email address into the registrable root domain. "https://www.Acme.co.uk/about?utm_source=x" and "[email protected]" both become acme.co.uk.

Uses the Public Suffix List, so multi-part suffixes like co.uk and com.au are handled correctly.
Turns LinkedIn company and person URLs into their canonical form and handle.
Flags freemail domains such as gmail.com and outlook.com.
Outputs a dedupe key you can match on.

How to read the result

Each row shows the input, the root domain, a LinkedIn handle where the input was a LinkedIn URL, and a freemail flag. Inputs that are not a domain, a URL or an email are marked invalid rather than guessed.

How to use it

Paste values one per line or drop a CSV and pick the column. Use the root domain as the key when you match a lead list against your CRM, a customer list or a suppression list. Use the freemail flag to keep personal addresses out of account-based matching, since gmail.com is not a company.

Why it matters for cold email

Dedupe and matching only work on clean keys. If one list has "https://www.acme.com/" and another has "acme.com", a plain match misses, and a customer ends up in a cold sequence. One canonical domain per company is also what lets you cap how many people you email at the same account.

Questions

What is a root domain?

The registrable domain: the part someone bought from a registrar. For blog.acme.com it is acme.com. For shop.acme.co.uk it is acme.co.uk, because co.uk is a public suffix and nobody owns "co.uk" itself.

Why not just strip www and https?

That fixes the easy cases and breaks the rest. Subdomains like mail. or eu. stay, and a rule that keeps the last two labels turns acme.co.uk into co.uk. The Public Suffix List knows which endings are suffixes, so the tool can cut at the right place.

What does it do with LinkedIn URLs?

It strips tracking parameters, country subdomains and trailing paths, and returns linkedin.com/in/<handle> for people and linkedin.com/company/<handle> for companies, plus the handle on its own. A Sales Navigator lead URL carries an internal ID rather than the public handle, so it cannot be converted offline and is marked.

How do I get the domain from an email address in Excel?

A formula like =RIGHT(A2,LEN(A2)-FIND("@",A2)) gives everything after the @, but it keeps subdomains such as mail.acme.com. Paste the column here to get the root domain and a freemail flag in one step.

Does it check that the domain exists?

No. It is a formatting step that runs in your browser, with no DNS lookups. To check whether a domain has working mail records, run it through the domain health check.