AscendLab

Developer tools

Email Address Validator

Free browser tool

Email Address Validator

Check email address syntax locally for pasted lists, signup QA, CSV cleanup, and support notes without sending data to a server.

Email list
Paste one email address per line for browser-side syntax checks.
Email validation result
2 of 3 addresses look syntactically valid.
[email protected]Valid syntax
[email protected]Valid syntax
bad-addressCheck syntax
Quick answer

This email validator checks syntax only.

It does not verify DNS records, SMTP response, mailbox existence, or deliverability.

Best inputs

One email per line

Line-separated lists are easiest to review.

Use for cleanup

Run syntax checks before importing a small list into another system.

Validation method
The tool applies a practical email syntax check locally.
Whitespace and missing @ signs are flagged.
Basic domain and top-level domain syntax is checked.
Results can be copied as JSON for notes.
Example, Assumption, and Limitation
Use the result as a practical estimate or transformation, then confirm edge cases for critical work.

Example

[email protected] passes a basic syntax check.

Assumption

You only need local syntax screening.

Limitation

It does not prove an address can receive mail.

Common use cases
These pages are built for lightweight browser-side work, examples, and planning.

CSV cleanup

Spot obvious syntax issues.

Signup QA

Test sample inputs.

Support notes

Review pasted addresses.

Docs

Show valid and invalid examples.

Frequently asked questions

Does this verify inbox existence?

No. It checks syntax only and does not perform DNS, SMTP, or mailbox verification.

Does it upload email addresses?

No. The syntax check runs locally in your browser.

Can I paste multiple emails?

Yes. Paste one address per line to get a simple validity summary.

Why not check deliverability?

Deliverability checks require network lookups and provider behavior, which is outside this pure frontend tool.

Suggested workflow

Email cleanup workflow

Validate syntax, clean CSV rows, then convert data if needed.