Free Email Deliverability Tools

11 tools for SPF, DMARC, blacklists, headers, signatures, and more. Built by the Review My Emails team.

Updated May 2026 · 11 tools, run in your browser · Most checks need no signup

Not sure where to start? Pick what's wrong.

Tap one. We'll point you at the right tool.

What "deliverability" actually means

Every legitimate email you send competes with billions of spam messages for inbox placement. Whether yours lands in the inbox, the promotions tab, the spam folder, or never arrives at all depends on three layered signals: authentication (does the receiver trust the message came from you), reputation (does your sending domain or IP have a clean record), and content quality (does the message look like something a human would want to read).

The tools on this page check those signals. Authentication tools like SPF, DMARC, and MTA-STS verify your DNS setup. The Blacklist Checker watches your reputation. The Header, Source, Signature, Accessibility, and Subject Line tools surface the content-quality issues most senders never look at.

You can run any tool on its own. Or pick the one that matches your problem from the diagnostic above and follow the "up next" links to the natural follow-on.

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Authentication & DNS

Verify your domain's email authentication setup and DNS records.

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Reputation & Monitoring

Monitor your sending reputation and decode email internals.

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Content & Design

Test your email content, signatures, and accessibility before you send.

Google or Yahoo just told you to set up DMARC?

Since February 2024, Google and Yahoo require DMARC for any sender mailing more than about 5,000 messages a day to their inboxes. If you got the notice and have no idea what DMARC is, we wrote a plain-English walk-through that gets you from "what is this" to a working record in under 15 minutes.

Google says I need DMARC. What do I do? →

Common questions

Which tool should I use first?
If your email is being rejected or you got a notice from Google or Yahoo about authentication, start with the SPF Checker and the DMARC Checker. If you have DMARC reports piling up and don't know what they mean, the DMARC Report Analyzer is the next step. If your domain is suddenly delivering badly, run the Email Blacklist Checker first to rule out a reputation problem.
Are these tools really free?
Yes. Every tool on this page runs on your domain or pasted content and returns results without a signup. A few tools ask for your email so we can stop bots and scammers from abusing the free tools, but the result is shown to you on the page either way. We do not require a credit card, a free trial, or an account.
Do you store the domains or emails I paste in?
We store the domain you check so we can offer to email a copy of the results if you ask for one. We do not store the full email content you paste into the header analyzer or signature analyzer beyond the time it takes to render the result. We do not sell or share what you submit.
What is email deliverability?
Email deliverability is the percentage of legitimate email that lands in the inbox instead of spam, promotions, or rejection. It depends on authentication (SPF, DKIM, DMARC), domain reputation (blocklists, complaint rate, engagement), and content quality (subject lines, signatures, accessibility). The tools on this page check the most common signals that affect inbox placement.
Google or Yahoo told me I need DMARC. What do I do?
Since February 2024, Google and Yahoo require DMARC for any sender mailing more than about 5,000 messages a day to their inboxes. Start with the DMARC Checker to see if your domain already has a record. If not, the DMARC Generator builds one for you. After your record is published, the DMARC Report Analyzer turns the daily XML reports into a readable summary.
Why do my emails go to spam?
The most common reasons are missing or broken email authentication (SPF or DMARC misconfigured), the sending domain is on a blocklist, the message looks spammy to filters (subject line, heavy HTML, tracking pixels), or low engagement on the recipient list. Run the SPF Checker, DMARC Checker, Blacklist Checker, and Subject Line Tester to narrow the cause.
Who built these tools?
The Review My Emails team. We are a small group of email deliverability specialists. We do hand-built deliverability reports for senders who want a deeper look. The tools here are how we surface the most common problems first, free, so you can fix the obvious things yourself.
Need help with email deliverability?

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