Test your email: paste the source, get the verdict
The well-known spam testers ask you to send them a real e-mail, because they need a mail server to receive it. This site has no server to receive anything — so instead you paste the message, and the browser does the whole analysis in front of you.
- Runs from your browser, not our server
- No sign-up
- No watermark
Loading the tool…
How it works
- Open the message in your mail program and take its source: “Show original” in Gmail, Ctrl+U in Thunderbird, “View message source” in Outlook on the web. Download the .eml file if you can — copying and pasting can change spaces and line breaks, and then the DKIM check (which compares the message character by character) fails.
- Paste it above, or drop the .eml file on the box.
- Press Analyse. Read the “Authentication” block first — it shows whether the mail proves who sent it, which is what receiving servers care about most — then the content rules, each with its own points.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see fetch the tool’s own code — and, for a few heavy tools, their open-source engine from a public CDN — plus one small page-view ping to loreatec.jp (page address and title, nothing more). None of them carry your file.
Frequently asked questions
Why paste the source instead of sending a test message?
Because receiving a message requires a mail server, and this site does not have one — everything here runs in your browser. The trade-off is fair: a spam tester that receives your mail can read it and keeps it for days; here it never leaves your computer. What is lost is the sending server’s address as a receiver would see it, so the tool reads it from the message’s own delivery headers instead, and lets you correct it.
How can it verify DKIM without a server?
DKIM is a digital signature that proves the mail really came from the sender’s domain and was not changed on the way. Checking it needs only two things browsers already have built in: a way to compute a fingerprint of the message and a way to check a signature against a public key. The tool prepares the message exactly as the standard (RFC 6376) requires, fetches the public key from DNS by name, and checks. It is tested against the official examples in RFC 8463, for both RSA and Ed25519 keys.
DKIM says the body does not match, but the mail arrived fine.
Almost always the paste is to blame. Copying a message through a browser can change tabs, spaces at the end of lines and line breaks, and the DKIM signature covers the body character for character. Download the original as a .eml file and drop it here instead. If it still fails with the .eml, something really did change the body after it was signed — a mailing-list footer, a banner added by an antivirus, or a forwarding server.
Is the score the same as the well-known one out of ten?
No, and it does not pretend to be. It is our own set of rules, and every rule is listed on the page with its points, so you can see exactly where the number came from. No score can predict where a mail will land: the biggest factor is your reputation as a sender with each receiver, and that is invisible from outside — to anyone, including the paid tools.
Why are some blocklists shown as “not checkable”?
A blocklist is a public list of addresses known to send spam. Some of them refuse questions that arrive through public DNS services, and a browser can only ask through public DNS services. Spamhaus, URIBL and SURBL answer with a code that means “I will not tell you”. Reporting that as “clean” would be the most dangerous kind of wrong, so the tool names them and links to their own lookup pages instead. The fifteen lists that do answer are checked normally.
Can I check a message without any network at all?
Yes — untick the DNS box. Everything that can be checked from the message alone still runs: headers, the delivery route, the structure, the HTML, the links, the legal requirements and the DKIM body check. Only the parts that really need DNS are marked “not checked”.