Don't land in SPAM anymore
Spam Checker by Mailmeteor helps you validate your emails before sending them. It detects spam words that look unnatural, shady, overpromise and more. By rephrasing or using synonyms, you avoid spam filters.
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How it works
Learn how to detect spam words in your emails with this 2-min video tutorial.
Trusted by 6 million professionals
Questions & answers about spam checker
Everything you need to know about spam filters and how to keep your emails in the inbox.
What does the spam checker actually look for?
Spam Checker looks for spam trigger words in your email. Spam words are keywords or expressions that email service providers see as red flags.
We divided spam keywords into 5 main categories:
- Urgency 🚨 - words that pressure recipients
- Shady 🔞 - ethically or legally questionable words
- Overpromise 🤩 - exaggerated claims
- Money 💰 - all things related to money in general
- Unnatural 💬 - words that don't feel natural
The tool highlights each match so you can rephrase in context. A single flagged word rarely sends an email to spam — the goal is to reduce cumulative signals.
Why do my emails go to spam even without trigger words?
Email content is only one of many signals. Other common reasons include:
- Missing authentication — no SPF, DKIM, or DMARC on your domain
- Poor sender reputation — recent bounces, complaints, or sending from a new domain
- High send volume — sudden spikes from a cold IP
- Bad list hygiene — invalid or role addresses on your list
- Too many links or images — especially with little plain text
Read our deliverability guide for a full checklist.
What are the Gmail and Yahoo bulk-sender rules?
Since February 2024, senders delivering more than 5,000 emails per day to Gmail or Yahoo users must:
- Authenticate mail with SPF, DKIM, and DMARC
- Use a visible, one-click unsubscribe link
- Keep the spam complaint rate below 0.3% (aim for under 0.1%)
Failing any of these can send your entire campaign to spam — regardless of content. Spam Checker only covers the content side; run a domain check too.
How do I fix an email flagged as spammy?
Work through these in order:
- Rephrase flagged words using natural synonyms — don't just delete them.
- Shorten aggressive phrases ("LIMITED TIME OFFER!!!" → "Ends Friday").
- Lower image-to-text ratio — aim for at least 200 words of real copy.
- Add a plain-text alternative if you're sending HTML.
- Preview in Gmail and Outlook before a full send — internal tests catch most issues.