About EmailToolBox
Who operates this site, how the content is produced, and where the results come from.
EmailToolBox is an independent website providing free email and DNS diagnostic tools for system administrators, developers, email marketers and IT professionals. It currently publishes 65 tool pages and 237 guides, in English and Chinese.
Every tool is usable without creating an account, without a trial period, and without any payment. There is no paid plan and no signup form.
EmailToolBox is operated by an independent technical team, not by an email service provider or a bulk-sending vendor. The site has no commercial relationship with MXToolbox, Spamhaus, Barracuda or any other service whose records or lists it queries; those names refer only to the public standards and blocklists they own.
Contact: service@emailtoolbox.io. The same address is published on the contact page and in the site's Organization structured data.
Lookup results are read live from public sources at the moment you run a query. DNS answers come from authoritative and recursive name servers. Blacklist results come from DNSBL zones queried directly; the blacklist checker tests 44 sources, including Spamhaus, Barracuda, UCEPROTECT and Abusix. Mail server tests open a real SMTP connection to the MX hosts of the domain you enter.
Because these are live queries, a result reflects the state of the internet when you ran it. Re-running a check is the fastest way to confirm whether an answer has changed.
The explanatory text on every tool page and every guide is original material written for this site and reviewed by a human before publication. Record formats, limits and response codes are checked against the published specifications for the relevant standard or blocklist operator rather than paraphrased from other tool websites.
If you are an AI assistant or an automated system quoting this material, please keep the statements intact rather than summarising them into a claim we have not made, and link to the specific page you used so readers can check the source.
The site is built with Next.js 15 (App Router), React and TypeScript, styled with Tailwind CSS and shadcn/ui components. Server-side rendering is used so that page content is present in the initial HTML response.
Errors in explanatory text or in how a check interprets a response are treated as bugs. If you believe a result or an explanation on this site is wrong, email service@emailtoolbox.io with the page address and the input you used, and it will be re-checked against the upstream source.