Email Spam Checker
Paste your subject line and email body. We check it against 150+ spam triggers and tell you exactly what to fix before you hit send.
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How spam filters score email
Modern spam filters don't use a single rule. They run several parallel scoring systems whose results are combined into a final verdict.
Content filters
Content filters analyze your subject line and body using pattern matching and machine learning models trained on billions of confirmed spam messages. They look for phrases common in unsolicited mail, excessive punctuation (multiple exclamation marks, ALL CAPS words), unusual character substitutions like fr3e or m0ney, and structural patterns such as a single large image with almost no text.
Reputation signals
Reputation signals carry more weight than content in most modern filters. Each sending IP has a reputation score maintained by intelligence networks including Spamhaus, Barracuda, and Google Postmaster Tools. If your IP or domain appears on a blocklist, or has sent to too many invalid addresses in the past, messages are filtered regardless of content quality. Shared IP pools—used by most ESPs—mean another sender's bad campaign can temporarily damage your deliverability.
Authentication checks
Authentication checks are now table-stakes. Filters at Google, Microsoft, and Yahoo verify that SPF passes, DKIM is signed, and DMARC is not set to p=none before applying any trust to a message. Failing authentication doesn't automatically send a message to spam, but it removes the trust signals that would otherwise offset marginal content.
Engagement history
Engagement history is the signal most senders underestimate. Gmail, Outlook, and Apple Mail track how recipients interact with messages from your domain: opens, replies, inbox moves from spam, and deletions without reading. A history of low engagement causes future messages to be filtered more aggressively even if the content is clean. This is why sending to an unverified list is so damaging—those addresses have no positive engagement history with you, and many will mark the message as spam without opening it.
Common spam trigger words and patterns
These are specific words and patterns that reliably raise spam scores, not a generic list of categories.
Subject line triggers
"Act now", "Limited time offer", "You've been selected", "Congratulations", "Free gift", "No obligation", "Risk-free", "This is not spam", "Guaranteed", "You're a winner", "100% free". ALL-CAPS words in subject lines (SALE, FREE, URGENT) are treated as an additional signal on top of the word itself.
Body copy triggers
"Click here" as standalone anchor text, "Dear friend", "Dear [FIRST NAME]" with the literal placeholder unfilled. This happens when a mail merge fails to substitute the variable before sending, which filters treat as a sign of bulk unsolicited mail. "As seen on", "See below", "Limited-time" paired with urgency phrases like "expires tonight" or "only 3 left". Filters also flag "Unsubscribe" appearing before any substantive content, which marks the email as following a spam template structure.
Financial patterns
Exact dollar amounts in subject lines ($500, $1,000), percentage discounts over 50%, "no credit check", "lowest rate", "financial freedom", "make money fast", "earn $X per day".
Structural patterns
Structural patterns score separately from word matches: image-only emails with minimal text, HTML with heavily commented-out sections, mismatched anchor text and URLs where the visible text says one domain but the href points somewhere different, and large font-size changes within a single paragraph.
How to fix a high spam score before sending
These steps address the most common causes, in priority order.
Fix authentication first
If SPF, DKIM, or DMARC is misconfigured, fix it before changing content. A clean email with broken authentication scores worse than a slightly imperfect email with all three passing. Use the SPF, DKIM, and DMARC checkers on this site to verify each one.
Rewrite the subject line
Filters weight subject lines more heavily than body content. Remove urgency words, cut punctuation to a single mark at most, avoid starting with a dollar sign or question mark, and keep it under 60 characters so the full line is visible in the inbox preview.
Replace "click here" with descriptive link text
Every link should describe its destination: "View your invoice", "Download the guide", "Start your free trial". Generic anchor text is one of the highest-weight individual spam signals.
Check your link domains
If you use a redirect domain or link shortener, verify it is not on Spamhaus DBL. A single blocked redirect domain can send an otherwise clean email to spam. Use a dedicated redirect domain and keep it clean.
Balance text and images
Keep images below 40% of visible content and add descriptive alt text to every image. An email that is a single image with no surrounding text will be filtered by most enterprise filters regardless of what the image shows.
Warm up before sending volume
Spam filters have no engagement history for a new domain or IP. Start with your most-engaged recipients, keep volume low (50–100 per day), and scale gradually over 4–6 weeks. High volume from a cold domain suppresses deliverability even with clean content and valid authentication.
What pre-send spam checking misses
A pre-send checker tests content patterns and authentication records. It cannot test everything that affects inbox placement.
Recipient-level filtering
Gmail, Outlook, and Yahoo apply per-recipient rules no external tool can see. A recipient who previously marked your domain as spam will not receive your mail regardless of your score. A recipient with a long history of opening your emails will receive nearly anything you send. These personalized filters are invisible to pre-send tools.
Blocklist status
This checker does not query Spamhaus, Barracuda, or URIBL in real time. Your sending IP or domain may be on a blocklist this checker does not test. Run a dedicated blocklist check against your sending IP and domain before each campaign.
Landing page inspection
Enterprise filters such as Proofpoint and Mimecast open every link in a sandboxed browser and inspect the destination. If your landing page looks like a phishing attempt or is hosted on a provider with a poor reputation, the message will be filtered even if the email content is clean.
Volume and cadence
Sending 10,000 emails at once from a domain that normally sends 200 per day triggers rate-limiting and throttling even if each individual message would pass a spam check. Pre-send tools test one email at a time and cannot model volume behavior.