Developer
Email Spam Tester
Send an email to the address below from the account or server you want to test. Our mail server receives it and explains, check by check, why it could land in spam and how to fix it.
Your test email is analysed on our server and deleted automatically after 7 days.
Frequently asked questions
Why do my emails go to spam?
Mailbox providers decide from several signals together. The most common causes are missing or failing authentication (no SPF record, no DKIM signature, or no DMARC policy for the From domain), a sending IP address or a domain in the message listed on a blocklist, a server without matching reverse DNS, and content that looks like spam: a single large image with little text, link text that points somewhere else, URL shorteners, or a subject in capitals. For bulk mail, a missing one-click unsubscribe and complaints from recipients weigh heavily. The report tests each of these on the email you actually sent.
What are SPF, DKIM and DMARC?
They are DNS records that let a receiving server check who sent an email. SPF lists the servers allowed to send for a domain, for example v=spf1 include:_spf.google.com -all. DKIM adds a cryptographic signature to each message, and the public key is published in DNS under a selector such as google._domainkey. DMARC, published at _dmarc.yourdomain, tells receivers what to do when a message fails both, for example v=DMARC1; p=quarantine; rua=mailto:reports@yourdomain, and requires the SPF or DKIM domain to match the From address (alignment).
What are the Gmail and Yahoo bulk-sender requirements?
Since February 2024, Gmail and Yahoo require every sender to have SPF or DKIM, a valid reverse DNS (PTR) for the sending IP and TLS, and to keep reported spam low. Senders of more than about 5,000 messages a day to Gmail must also have SPF and DKIM and a DMARC record (p=none is enough), an aligned From domain, and a one-click unsubscribe: a List-Unsubscribe header with an https link plus List-Unsubscribe-Post: List-Unsubscribe=One-Click. Microsoft Outlook.com applied similar rules to high-volume senders in 2025. The bulk-sender section of the report checks your message against these rules.
How is the score calculated?
Every message starts at 10 points. Points are taken off for failed or missing SPF, DKIM and DMARC, for a missing or mismatched reverse DNS, for listings on the blocklists we query (Spamhaus, Barracuda, SpamCop, UCEPROTECT, PSBL, Mailspike and others, and Spamhaus DBL, SURBL and URIBL for domains), for spam filter rules and for content problems. The spam filter is Rspamd, the open-source filter many mail servers use; its rules are shown with their scores. Each check shows how many points it cost. The score is a guide: Gmail, Outlook and Yahoo also use sender reputation and recipient feedback that no outside test can see.
Is my email stored? Who can see the report?
The message is received and analysed on our server in Germany and is not sent to any other company. The message and the report are deleted automatically after 7 days, and you can delete them at once with the Delete button. Anyone with the report link can open the report, so share it only with people you trust. The full raw message and its headers can be viewed only from the browser that created the test. Please don’t send passwords or other secrets in a test email.
Can I send several emails to the same address?
No. Each test address accepts one message and stops accepting mail after 60 minutes, so a report always belongs to one email. To test again after a change, press Test another email to get a new address. There is a limit on how many tests one IP address can start per hour.
Can I test from Gmail, Outlook or my own mail server?
Yes. Send from any mailbox or sending service: Gmail, Google Workspace, Outlook, Microsoft 365, a newsletter platform, a transactional email API or your own Postfix or Exchange server. The report then shows the real path your email took: the server that delivered it, its reverse DNS and TLS, and the signatures it added. Our server only receives mail; it never sends, forwards or replies.
My score is 10 but my emails still go to spam. Why?
A clean technical setup is necessary but not always enough. Large mailbox providers also look at the reputation of your domain and IP address over time, how many recipients open, delete or mark your emails as spam, sending volume spikes and whether you mail old or bought lists. Use Google Postmaster Tools and Microsoft SNDS to watch your reputation, send only to people who asked for your emails, and remove addresses that bounce.
About this tool
An email spam tester answers a simple question: if I send this email, what will a receiving mail server think of it? This one works like a real recipient. The address on this page belongs to our mail server, so when you send to it, your email travels over the internet exactly as it would to a customer, and we analyse what arrives: the connection from your server, the authentication records in DNS, the signatures in the headers, the blocklists and the content. You get a score out of 10, a list of the problems that matter most, and a fix for each one.
Authentication is the first thing to get right. SPF (Sender Policy Framework) is a TXT record on your domain that lists the servers allowed to send for it, such as v=spf1 include:_spf.google.com -all for Google Workspace; use a single SPF record and stay within its limit of 10 DNS lookups. DKIM (DomainKeys Identified Mail) signs every message with a private key held by your mail provider; you publish the public key, usually a 2048-bit RSA key, under a selector like selector1._domainkey.yourdomain.com. DMARC ties both to the address people see in the From line: publish v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com at _dmarc.yourdomain.com to start receiving reports, then move to p=quarantine and p=reject once all your legitimate mail passes.
The server that sends your mail matters as much as the domain. Its IP address should have a reverse DNS (PTR) name whose A record points back to the same IP, a check called forward-confirmed reverse DNS or FCrDNS, and it should introduce itself in HELO with that name. Names that look like a home or dynamic connection, such as ip-203-0-113-7.dynamic.example.net, are treated with suspicion. Mail should be delivered over TLS. The IP address and every domain in the message are checked against public blocklists: a listing on Spamhaus ZEN, Spamhaus DBL or Barracuda alone can send mail to spam or get it rejected, and the report links to each list’s removal page.
Content is the last layer. Spam filters such as Rspamd and SpamAssassin score hundreds of small signals: an HTML-only email with no plain-text version, mostly images with little text, link text that shows one address while the link goes to another, URL shorteners, hidden text, a subject in capitals or full of exclamation marks, missing Date or Message-ID headers, or a Reply-To on a different domain. None of these is fatal alone, but together they add up. For newsletters and other bulk mail, Gmail and Yahoo also require a working one-click unsubscribe (List-Unsubscribe with List-Unsubscribe-Post) and honour it within two days.
The test is private by default. Each address is random, accepts a single message and expires after an hour; the message and report are deleted after 7 days. The report link can be shared with a colleague or your email provider’s support team, while the raw source stays visible only in the browser that created the test.