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MailTester
What it is
MailTester checks why emails may land in spam and assigns each message a deliverability score out of 10. To run a test, create a disposable address, send the email to it, and receive a report in seconds. The score begins at 10 and falls when issues are found; the report explains penalties and suggests fixes. Checks include 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 messages and reports a spam score with triggered rules. Newsletter tests include one-click List-Unsubscribe (RFC 8058), message size, and text-to-image ratio. MailTester is available on web, API, and self-hosted platforms. Its API can create test addresses and return report status and scores as JSON. The free plan costs nothing, requires no account, and provides 25+ checks per test. The maker says its testing systems run on its own infrastructure and messages are kept only as long as needed to show the report.
For and against
For
- Free plan requires no account.
- Checks SPF, DKIM, DMARC, and DNS configuration.
- Tests sending IPs against multiple blocklists.
- Reports include a score and suggested fixes.
- API returns report status and scores as JSON.
Against
- Free plan provides 25+ checks per test.
- No free trial is listed.
- Pricing beyond the free plan is available on request.
The verdict
MailTester gives email senders a report that connects deliverability issues with a score and suggested fixes. Its no-account free plan offers a straightforward starting point, while API access and tailored pricing are available for other needs.
Who it suits
MailTester suits people checking email deliverability, monitoring multiple domains, or seeking API access and a tailored plan. Newsletter senders can use its checks for unsubscribe handling, message size, and text-to-image ratio.
Plans and prices
Free
No account needed · 25+ checks per test
Read 7 Oct 2026 · mailtester.eu
On the record
- API
- The API can create test addresses and read report status and scores as JSON.mailtester.eu · read 7 Oct 2026
- Authentication checks
- It checks SPF, DKIM, DMARC, domain alignment, reverse DNS, and forward-confirmed reverse DNS.mailtester.eu · read 7 Oct 2026
- Blacklist checks
- It checks sending IPs against Spamhaus, SpamCop, Barracuda, and other DNS blocklists.mailtester.eu · read 7 Oct 2026
- Bulk email checks
- The service checks one-click List-Unsubscribe (RFC 8058), message size, and text/image ratio for newsletter testing.mailtester.eu · read 7 Oct 2026
- Content analysis
- It analyzes HTML, text/image ratio, links, subject, List-Unsubscribe, and Message-ID.mailtester.eu · read 7 Oct 2026
- Data retention
- The FAQ says messages are kept only as long as needed to show the report.mailtester.eu · read 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.mailtester.eu · read 7 Oct 2026
- Intended users
- The maker invites users to test deliverability, monitor multiple domains, or request API access and a tailored plan.mailtester.eu · read 7 Oct 2026
- Privacy
- The maker describes the .eu edition as configured for full GDPR compliance.mailtester.eu · read 7 Oct 2026
- Purpose
- MailTester checks why emails may land in spam and returns a deliverability score out of 10.mailtester.eu · read 7 Oct 2026
- Scoring
- The score starts at 10, subtracts points for detected issues, and explains penalties with suggested fixes.mailtester.eu · read 7 Oct 2026
- Spam analysis
- Messages are analyzed by Rspamd, with a spam score and a list of triggered rules.mailtester.eu · read 7 Oct 2026
- Support
- The contact page says inquiries receive a reply within one business day.mailtester.eu · read 7 Oct 2026
- Test workflow
- Generate a disposable address, send the email to it, and receive a report in seconds.mailtester.eu · read 7 Oct 2026
