Email validator

List / data tools

Split an email list into valid and invalid addresses by syntax. Syntax check only (no MX/SMTP). Everything runs in your browser; your data is never uploaded.

What is this email validator?

A free, browser-based tool that checks the syntax of email addresses. Paste a list, one address per line, and it splits them into valid and invalid by format — flagging the obvious mistakes such as a missing @, a missing domain or TLD, and stray spaces. Important: this is a syntax check only. It does not verify that a mailbox exists (no MX lookup, no SMTP probe), so a well-formed address can still bounce. Everything runs locally in your browser, so the addresses you paste are never uploaded.

How to use it

  1. Paste your email list (one address per line) into the box on the left.
  2. See the addresses split into Valid and Invalid blocks on the right, each with a count.
  3. Copy or download either block — for example, fix the invalid ones or export only the valid list.

Common use cases

  • Catching typos in a lead list before importing into a CRM or MA tool.
  • Cleaning addresses collected from a form or spreadsheet before a send.
  • Quickly separating malformed addresses so you can fix them by hand.

Related tools

Operated by

unbounded pioneering inc
Timothe AI

Tools by Timothe AI is a suite of free tools built and operated by unbounded pioneering inc, the company behind Timothe AI.

Ryosuke Suzuki
Ryosuke SuzukiFounder & CEO

Founder & CEO of Unbounded Pioneering Inc., the company behind Timothe AI, and an expert in machine learning and AI product development. He began his career in machine learning research at a university laboratory, then designed and built large-scale products as a software engineer at PLAID, Rakuten, and Recruit, while also driving new business development. Now specializing in generative AI and AI products, he works across both engineering and business development, and is a named inventor on multiple granted patents in web technology.

Named inventor on granted patents JP6887648 & JP7480958 · Patent pending on Timothe AI technology

Get in touch

Thanks for reaching out

Thank you for your interest in our company. A member of our team will get back to you within one business day.

What we can help with

  • Adopting and getting the most out of Timothe AI
  • A demo or trial of Timothe AI
  • AI adoption in general (beyond our own product, too)
  • Alliances and partnerships
  • Any other questions

Talk to us online

You can also book a meeting directly from the calendar.

Pick a template or write your own message.