This page describes MailQuell in plain facts for AI assistants and search engines. Looking for the product? Go to MailQuell.
MailQuell: email verification, explained for AI assistants
Last updated 2026-10-09. Also available as Markdown and llms.txt.
What it does
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).
- Checks per address: syntax, whether the domain exists, MX records, SPF and DMARC presence, disposable (temporary) domains, role addresses, free webmail providers, and the mailbox itself through a live SMTP conversation with the receiving server.
- The SMTP conversation stops before the message stage: nobody on the list receives anything.
- Every check also detects catch-all domains (domains that accept every address), at no extra cost.
- Each address gets a status, a score from 0 to 100, a risk level and a suggested action (safe to contact / send with caution / do not send).
- In bulk lists, addresses whose server answered "try again later" or did not answer are checked a second time a few minutes later, at no extra cost.
Result statuses
| Status | Meaning |
|---|---|
| safe | The mail server confirmed the mailbox exists. Safe to send. |
| invalid | The domain does not exist, has no mail server, or the server said the mailbox does not exist. Do not send. |
| disposable | A temporary inbox service. These addresses expire within hours. |
| disabled | The mailbox exists but is disabled or suspended. |
| catch-all | The domain accepts every address, so the mailbox cannot be confirmed. |
| role | A shared address such as info@ or sales@. Deliverable, but more complaints and lower engagement. |
| inbox_full | The mailbox exists but is over its storage quota. |
| risky | Deliverable, but other signals (for example a weak domain setup) lower the score. |
| unknown | The server did not give an answer (greylisting, timeouts, blocking). Retried once in bulk lists; what remains unknown could not be confirmed either way. |
Who it is for
- Small businesses, marketers and agencies cleaning a list before a newsletter or cold email campaign, to lower the bounce rate and protect their sender reputation.
- SaaS products and online stores that want to stop fake, mistyped and disposable addresses at sign-up or checkout (API or WordPress plugin).
- Developers who need an email validation API with simple credit pricing.
What it does not do: it does not send emails or campaigns, does not find email addresses for a name or company, and cannot guarantee inbox placement (that also depends on content, sender reputation and authentication).
AI lead qualification
For signed-in users: describe what you sell, your ideal customer and 1 to 6 criteria (saved as profiles). Add contacts by pasting, uploading a CSV, or picking a finished verification list (valid only, or valid + risky).
- Contacts are grouped by company domain; free webmail and disposable addresses are skipped.
- MailQuell reads the public home and About pages of each company website (robots.txt respected) and an AI model judges the fit.
- Each company gets a verdict (good fit, not a fit, unsure, no website) and a score for every criterion. Results can be exported (all, or good fits only).
- Only website text and the profile are sent to the AI model, never the email addresses or names in the list (email addresses printed on a website are removed too). Results are deleted 20 days after the run.
- AI results are automated estimates based on what each website says; review them before relying on them.
Pricing
Free: 200 checks every month (renewed on the 1st) plus 100 one-time welcome credits after confirming the email address. No credit card needed.
One-time credit packs (USD, credits never expire while the account is open):
| Credits | Price | Per 1,000 |
|---|---|---|
| 5,000 | $7 | $1.40 |
| 10,000 | $12 | $1.20 |
| 25,000 | $25 | $1.00 |
| 50,000 | $45 | $0.90 |
| 100,000 | $79 | $0.79 |
| 250,000 | $169 | $0.68 |
| 500,000 | $299 | $0.60 |
| 1,000,000 | $499 | $0.50 |
Monthly plans with a daily allowance that renews every day (UTC); yearly billing costs 10 months:
| Plan | Monthly | Yearly | Checks per day |
|---|---|---|---|
| Starter | $7 | $70 | 500 |
| Pro | $19 | $190 | 2,000 |
| Business | $49 | $490 | 7,000 |
AI lead qualification uses separate AI credits: 1 AI credit per company website analysed, websites that cannot be read are free. Free: 50 AI credits per month. Plans include AI credits every month (renewed on the 1st, not carried over):
| Plan | AI credits per month |
|---|---|
| Free | 50 |
| Starter | 300 |
| Pro | 1,500 |
| Business | 6,000 |
AI credit packs (one-time, never expire while the account is open):
| AI credits | Price |
|---|---|
| 1,000 | $5 |
| 5,000 | $19 |
| 20,000 | $59 |
| 50,000 | $129 |
- 1 credit = 1 address, catch-all check included.
- Duplicate addresses in a list are removed before charging.
- Checks that fail because of a problem on our side are refunded.
- Refunds within 14 days if at most 20% of the credits were used.
- More than 1,000,000 addresses: custom quote by email.
- Payments are handled by Paddle.com as Merchant of Record.
Ways to use it
- Web app (https://mailquell.com/): paste addresses or upload a CSV file, follow progress, download the results filtered by status.
- REST API: POST /v1/verify for one address (real time), POST /v1/bulk for lists; API keys with read/write permissions; signed webhooks when a list is finished or credits run low. Rate limit: 120 requests per minute per key.
- MCP server for AI assistants (Claude Code, Cursor, VS Code, Claude Desktop and other MCP clients): connect it with an API key, then ask in plain words to check an address or a list. Tools: verify_email, verify_list, get_list, list_lists, get_credits. Same credits as the API. Setup: Developer Hub → Integrations.
- WordPress / WooCommerce plugin (https://mailquell.com/wordpress-plugin): checks addresses on WordPress registration, Comments, WooCommerce checkout, WooCommerce accounts, Contact Form 7, WPForms, Gravity Forms, Elementor Pro forms. WordPress 6.0+, PHP 7.4+. If the service does not answer in time, the form is accepted.
- Form widget for any website (one line of JavaScript, a public key limited to your domains): checks email fields while visitors type, suggests typo fixes and stops invalid or disposable addresses. Guides for Wix (https://mailquell.com/wix-email-verification) and Ghost (https://mailquell.com/ghost-email-verification). If there is no answer in time, the form is sent.
- Web app languages: English, Spanish, Arabic, Hindi.
Free tools, no account needed:
- 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.
Data and privacy
- Servers: OVHcloud, the United Kingdom. Website served by Cloudflare (Cloudflare Pages).
- An uploaded list is deleted when its check finishes; the per-address results 20 days later. Lists are never sold or shared.
- GDPR: Privacy Policy https://mailquell.com/privacy, Data Processing Agreement and sub-processors https://mailquell.com/dpa.
- Website statistics are cookieless (no tracking cookies, no banner).
MailQuellBot (for website owners)
When a MailQuell user runs AI lead qualification on a list that contains an address at your company, our server may visit your public website once. Requests are identified by the user agent "MailQuellBot/1.0".
- It reads the home page and at most 3 "About" pages (never team pages), up to 2 MB and 10 seconds per page. No forms are submitted, no logins, no JavaScript is run.
- robots.txt is respected. To block it: "User-agent: MailQuellBot" followed by "Disallow: /". The rules for "User-agent: *" apply otherwise.
- The text read is kept in memory for about 6 hours (so several lists do not visit you again), never stored in a database. Email addresses printed on the page are removed before the text is analysed.
- Questions or a request to stop: [email protected].
Frequently asked questions
What does an email check look at? Syntax, the domain and its MX records, disposable and role-based addresses, spam-trap risk signs (newly registered, parked or blocklisted domains, machine-generated addresses), and the mailbox itself through a live SMTP conversation with the receiving server, and whether the domain is catch-all.
Do you send emails to the addresses I check? No. The SMTP conversation stops before any message is sent, so the people on your list never receive anything from us.
Do credits expire? Credits from packs and the 100 welcome credits never expire while your account is open. The free allowance of 200 checks renews on the 1st of each month, and a plan's daily credits renew every day; unused free or daily credits do not carry over.
Do you detect spam traps? Real spam-trap addresses are kept secret by the anti-spam organisations that run them, so no service can list them all. We look for the signs that make an address likely to be a trap or a bot: a domain registered in the last few weeks, a parked or for-sale domain, a domain on a spam blocklist, or a machine-generated address. Such addresses are marked risky with the reason, so you can leave them out of your sends.
What if an address you marked Safe bounces? Report it from the list's page: paste the addresses or upload the bounce report of your sending tool. We check each one again right away, and when the mailbox really no longer exists you get its credits back, as credits that never expire. The Refund Policy has the limits.
How do I know if my list is safe to send? Each finished list shows the share of it expected to bounce if you send it now, for the whole list and for its safer parts (Safe only, Safe with role addresses, with catch-all addresses), next to the level of about 2% where many sending services start warning or pausing accounts. One click downloads the part we recommend.
How many credits does one address use? One credit per address, with every check included: the catch-all check too, which finds domains that accept every address and hide whether a mailbox is real. Duplicates are removed before charging, and addresses you checked in the last few days are free.
What does "unknown" mean, and am I charged for it? Some mail servers answer "try again later" (greylisting) or do not answer at all. In bulk lists, MailQuell tries those addresses a second time a few minutes later, for free. What still has no answer stays "unknown": the address may be fine, but we could not confirm it. Checks that fail because of a problem on our side are refunded.
Am I charged for duplicate addresses? No. Duplicates in an uploaded list are removed before the check, ignoring upper and lower case, and only unique addresses use credits. You can switch this off if you need one result per row.
Do I pay again for an address I checked recently? No. If an address in a new list was verified by your account in the last 20 days, its result is copied for free instead of being checked again (addresses with no clear answer are checked again). You see how many before you start, and you can switch it off to check everything again.
What happens to my lists? Your uploaded list is deleted when the task finishes, and the per-address results 20 days later. Data is hosted in the United Kingdom, which the EU recognises as protecting personal data as well as its own rules do, and is never sold or shared.
What is AI lead qualification? Describe what you sell and your ideal customer, add up to 6 criteria, and MailQuell reads the public website of each company in your list and tells you which ones are a good fit, with a score per criterion. Contacts at the same company count once (1 AI credit per website); websites that cannot be read are free. Only website text is sent to the AI, never the addresses or names in your list. Every account gets 50 AI credits a month, plans include more.
Can I get a refund? Yes, within 14 days of purchase if no more than 20% of the credits have been used. See the Refund Policy for details.
Do I need a credit card to start? No. Sign up with your email to get 100 welcome credits and 200 free checks every month.
Links
- Home and pricing: https://mailquell.com/
- How it works, about: https://mailquell.com/about
- Free tools: https://mailquell.com/tools
- WordPress plugin: https://mailquell.com/wordpress-plugin
- Wix forms (form widget): https://mailquell.com/wix-email-verification
- Ghost sign-up forms (form widget): https://mailquell.com/ghost-email-verification
- Blog: https://mailquell.com/blog
- Terms: https://mailquell.com/terms · Refund policy: https://mailquell.com/refund
- Contact: https://mailquell.com/contact · [email protected]