# MailQuell

> MailQuell is an online email verification service. It checks whether email addresses exist and can receive mail, without sending any email, so senders can remove invalid, disposable and risky addresses before a campaign. It works in the browser (paste or upload a CSV), through a REST API, and as a WordPress/WooCommerce plugin, with pay-as-you-go credits from $7 and 200 free checks every month. Signed-in users can also run AI lead qualification: MailQuell reads each company's public website and estimates whether it matches the customer profile they describe (50 free AI credits a month).

Full facts (pricing, statuses, API, privacy) in one file: https://mailquell.com/llms-full.txt

## Product

- [Pricing and overview](https://mailquell.com/): free plan, credit packs, monthly plans, FAQ
- [Facts for AI assistants](https://mailquell.com/ai): what MailQuell does and does not do, result statuses, pricing tables
- [About](https://mailquell.com/about): how the checks work, where data is stored
- [WordPress / WooCommerce plugin](https://mailquell.com/wordpress-plugin): stop fake and disposable addresses on forms and checkout
- [Wix forms](https://mailquell.com/wix-email-verification) and [Ghost sign-ups](https://mailquell.com/ghost-email-verification): the same check with one line of code (form widget)
- [AI lead qualification](https://mailquell.com/ai): which companies in a list match your ideal customer, judged from their public websites; MailQuellBot details for website owners

## Free tools

- [Email Checker](https://mailquell.com/tools/email-checker): Check if an email address is real and can receive mail, without sending anything.
- [Email List Organizer](https://mailquell.com/tools/email-list-organizer): Sort a list by domain, spot contact@, sales@ and hr@ addresses, and count Gmail, Yahoo and Outlook accounts.
- [MX Lookup](https://mailquell.com/tools/mx-lookup): See which mail servers receive email for a domain, in priority order.
- [SPF & DMARC Checker](https://mailquell.com/tools/spf-dmarc-checker): Check a domain's SPF and DMARC records and get fixes in plain language.
- [Disposable Email Checker](https://mailquell.com/tools/disposable-email-checker): Detect throwaway email addresses from temporary inbox services.

## Guides

- [Email Bounce Codes Explained: What 550 5.1.1, 421, 5.7.26 and Other SMTP Errors Mean](https://mailquell.com/blog/smtp-bounce-codes): How to read an SMTP bounce code, the difference between hard and soft bounces, and what to do about the most common errors from Gmail, Outlook and other servers.
- [How to Clean an Email List Before a Cold Email Campaign (Step by Step)](https://mailquell.com/blog/clean-email-list-before-cold-email): A practical process to verify and clean a cold email list: which addresses to remove, how to treat catch-all and unknown results, and how to keep bounces under 2%.
- [What Is a Catch-All Email Address? How to Verify and Handle Accept-All Domains](https://mailquell.com/blog/catch-all-email): Catch-all domains accept mail for any address, so no verifier can confirm the mailbox. Here is how they work, how to detect them and how to send to them safely.
- [Gmail, Yahoo and Outlook Sender Requirements in 2026: The Complete Checklist](https://mailquell.com/blog/email-sender-requirements-2026): What Gmail, Yahoo and Microsoft Outlook require from email senders in 2026: SPF, DKIM, DMARC, spam rate limits and one-click unsubscribe, with a setup checklist.

## Optional

- [Privacy Policy](https://mailquell.com/privacy)
- [Data Processing Agreement](https://mailquell.com/dpa)
- [Security](https://mailquell.com/security)
- [Terms of Service](https://mailquell.com/terms)
- [Refund Policy](https://mailquell.com/refund)
- [Contact](https://mailquell.com/contact)