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Email Syntax Checker

Check an email list for clear syntax errors and exact duplicates locally, without claiming inbox verification.

Local list check. Paste addresses separated by lines, commas, or semicolons. The list stays in this browser tab and is never sent to an email service.

0 / 200,000 characters · up to 10,000 entries

Syntax is not deliverability. This tool checks a practical email-address format and exact duplicates. It does not contact domains, send email, check inboxes, or guarantee delivery.

Data handling

Storage and export controls

Retention
The tool's working state is kept only while this page is open. Inputs and results are not saved to persistent storage by Got A Tool.
Export
The tool may prepare a result after you run it. It downloads or copies it only when you choose that action.

Advertising and analytics are separate site services. We do not send selected tool input to them. Read the Privacy Policy for details.

How it works

Clean an address list without claiming inbox verification

01

Paste a list

Use lines, commas, or semicolons between addresses.

02

Review results

Read syntax issues and exact duplicates before keeping the valid list.

03

Export carefully

Copy or download unique addresses that passed the local format check.

Important limit

A valid shape is not proof of delivery.

This page checks a practical address format. It does not contact a domain, inbox, or email provider, and it never claims that an address can receive mail. Treat the result as a list-cleaning step, then follow consent and sending requirements.

Local list check

Pasted addresses remain in your browser tab.

Exact duplicates

Matches ignore letter case but do not guess aliases.

Visible issues

Malformed entries stay available for review.

No delivery claim

No inbox or domain verification is attempted.

FAQ

Common questions

Can this tell whether an inbox exists?

No. It never contacts an email provider or mailbox.

Are Gmail aliases duplicates?

No. This page checks exact addresses after normalizing letter case. Use Gmail Alias Duplicate Finder for that narrower review.

Does this upload contacts?

No. The list is processed locally in your browser.

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