MailTester
MailTester checks why emails may land in spam and gives each message a deliverability score out of 10.
What MailTester is
MailTester checks why emails may land in spam and gives each message a deliverability score out of 10. To run a check, generate a disposable address, send an email to it, and receive a report in seconds. The score starts at 10 and decreases when issues are detected; the report explains penalties and suggests fixes. Checks cover SPF, DKIM, DMARC, domain alignment, reverse DNS, and forward-confirmed reverse DNS, as well as sending IPs against Spamhaus, SpamCop, Barracuda, and other DNS blocklists. Content analysis reviews HTML, text-to-image ratio, links, subject, List-Unsubscribe, and Message-ID. Rspamd analyzes each message and reports a spam score with triggered rules. Newsletter checks include one-click List-Unsubscribe (RFC 8058), message size, and text-to-image ratio. MailTester is available on web, API, and self-hosted platforms. The API can create test addresses and return report status and scores as JSON. The free plan requires no account and offers 25+ checks per test. The maker says messages are kept only as long as needed to display the report.
Good
- Reports a deliverability score out of 10 with suggested fixes.
- Checks authentication records and sending-IP blocklists.
- Rspamd reports spam scores and triggered rules.
- Free plan requires no account.
- Available on web, API, and self-hosted platforms.
Watch out
- No free trial is listed.
- Pricing beyond the free plan is on request.
- Messages are retained while needed to show reports.
Who it suits
MailTester may suit people checking email deliverability, monitoring multiple domains, or seeking API access and a tailored plan. Newsletter senders can use its bulk-email checks for unsubscribe handling, message size, and text-to-image ratio.
Verdict
MailTester brings authentication, blacklist, and content checks together in a report with a score and suggested fixes. Its free plan requires no account; pricing beyond that is available on request.
Plans and prices
From MailTester's own pricing page, checked 7 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free | Free | No account needed · 25+ checks per test |
The facts
Each one read from MailTester's own pages, with the date it was checked.
What it does
- API
- The API can create test addresses and read report status and scores as JSON.checked 7 Oct 2026
- Authentication checks
- It checks SPF, DKIM, DMARC, domain alignment, reverse DNS, and forward-confirmed reverse DNS.checked 7 Oct 2026
- Blacklist checks
- It checks sending IPs against Spamhaus, SpamCop, Barracuda, and other DNS blocklists.checked 7 Oct 2026
- Bulk email checks
- The service checks one-click List-Unsubscribe (RFC 8058), message size, and text/image ratio for newsletter testing.checked 7 Oct 2026
- Content analysis
- It analyzes HTML, text/image ratio, links, subject, List-Unsubscribe, and Message-ID.checked 7 Oct 2026
- Data retention
- The FAQ says messages are kept only as long as needed to show the report.checked 7 Oct 2026
- Infrastructure
- The maker says the SMTP server, authentication checks, blacklist queries, and Rspamd engine run on its own infrastructure, with no data leaving its perimeter.checked 7 Oct 2026
- Intended users
- The maker invites users to test deliverability, monitor multiple domains, or request API access and a tailored plan.checked 7 Oct 2026
- Privacy
- The maker describes the .eu edition as configured for full GDPR compliance.checked 7 Oct 2026
- Purpose
- MailTester checks why emails may land in spam and returns a deliverability score out of 10.checked 7 Oct 2026
- Scoring
- The score starts at 10, subtracts points for detected issues, and explains penalties with suggested fixes.checked 7 Oct 2026
- Spam analysis
- Messages are analyzed by Rspamd, with a spam score and a list of triggered rules.checked 7 Oct 2026
- Support
- The contact page says inquiries receive a reply within one business day.checked 7 Oct 2026
- Test workflow
- Generate a disposable address, send the email to it, and receive a report in seconds.checked 7 Oct 2026
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