Comparison, checked October 2026
A free first pass before you pay ZeroBounce or NeverBounce
List Desk is a free email list validator by Przemysław Zalewski, an independent engineer. It removes what is plainly broken before you pay for verification; it does not probe mailboxes, and ZeroBounce and NeverBounce do.
By: Przemysław Zalewski ·
TL;DR
- List Desk does not check whether a mailbox exists. It checks syntax, duplicates, the domain in DNS, disposable and role addresses and typos, for free, without sign-up, in your browser.
- ZeroBounce and NeverBounce talk to the recipient’s mail server (SMTP) and tell you whether the mailbox accepts mail, and flag catch-all domains. For that, they are the right tool.
- Used together: clean the list for free first, then send only what is left to a paid verifier, if your campaign needs mailbox-level results.
What each one checks
Only what each service states on its own website, as of October 2026. A dash means List Desk does not offer it.
| Check | List Desk | ZeroBounce | NeverBounce |
|---|---|---|---|
| Mailbox exists (SMTP check) | Not yet | Yes | Yes |
| Catch-all domains flagged | – | Yes (catch-all status) | Yes (accept-all result) |
| Disposable addresses | Yes (public list of 9,900+ domains) | Yes | Yes |
| Role addresses (info@, sales@) | Yes | Yes | Yes |
| Typo suggestions | Yes | Yes (did_you_mean) | Yes (suggested correction) |
| Bulk file upload | CSV, XLSX, TXT, read in the browser | CSV, TXT, XLS, XLSX | CSV |
| Real-time API | – | Yes | Yes |
| Free use | Up to 50,000 addresses per check, no account | 100 verifications a month with a business email domain | See their pricing page |
| Smallest paid package | Free | $39 for 2,000 addresses | Pay as you go (see their pricing page) |
Prices are from the official pricing pages as of October 2026 and change; check them before you buy.
When the free pass is enough
- The list came from your own sign-up form or CRM and you mainly want to catch typos (gmial.com), dead company domains and throwaway addresses before a newsletter.
- You are deduplicating and tidying a list from several spreadsheets: duplicates, including Gmail dots and +tags that land in the same mailbox, and addresses with broken syntax.
- You want to see how bad a list is before paying for anything. The result shows how many addresses would be removed and why.
- The list must not leave your computer. List Desk reads the file in the browser.
When you need SMTP verification
If you send cold email to a bought or scraped list, or to an old list you have not mailed in months, many addresses look fine in DNS but the mailbox is gone. Only an SMTP check catches those before they become hard bounces. ZeroBounce and NeverBounce do that, flag catch-all domains, and ZeroBounce also flags suspected spam traps and abuse addresses. List Desk does none of this yet.
They also fit when you need verification inside your own product: both offer a real-time API for sign-up forms, which List Desk does not.
Privacy: where your list goes
With List Desk the file is read in your browser. Addresses are never sent to the server; only the unique domains are, to look them up in DNS. Analytics records counts, never addresses or domains.
ZeroBounce and NeverBounce verify on their servers, which is required for an SMTP check. ZeroBounce says it keeps validation results up to 30 days and then deletes them, and that you can delete your files at any time. NeverBounce says your data is never resold and that it follows GDPR. If your list contains personal data, read their terms and data processing agreement before uploading.
Clean the list for free, then decide
The free check takes a CSV or Excel file of up to 50,000 addresses. If you send at volume and want the rest done properly (one-click unsubscribe, suppression lists, bounce and complaint handling, SPF, DKIM and DMARC aligned), that is work I take on.
Questions
Is List Desk a replacement for ZeroBounce or NeverBounce?
Not for mailbox verification. List Desk does validation (syntax, DNS, disposable, typos, roles, duplicates); ZeroBounce and NeverBounce also ask the recipient’s server whether the mailbox exists. Use List Desk as a free first pass and a paid verifier when you need mailbox-level results.
Does cleaning the list first lower what I pay for verification?
Both services sell credits per address checked, so every duplicate, dead domain or typo you remove first is one address fewer to send for paid verification.
What about catch-all addresses?
A catch-all domain accepts mail for any address, so no SMTP check can confirm a single mailbox there. ZeroBounce and NeverBounce flag these so you can decide how to treat them; List Desk does not detect them yet.
Is my list uploaded anywhere when I use List Desk?
No. Open the browser network tab while it runs: only lists of domains are sent, to look them up in DNS. See the tool page for what is stored.
Will List Desk add mailbox checks?
It is the next step. Leave your email on the tool page to hear when it is ready.
