Mail-Tester alternatives: free spam score and deliverability checkers

Mail-Tester is the classic free spam-score tool: you send it a test email and it replies with a 0-10 score plus the reasons. It's useful, but it tests one message at a time and doesn't look at your domain's full authentication stack or IP reputation. Here are the best alternatives, depending on what you actually need.

Best free, no-signup alternative: Inboxproof

Inboxproof checks your domain instead of a single email. In about 30 seconds it runs MX, SPF, DKIM, DMARC, TLS, PTR and IP reputation (RBL) checks, then gives you one 0-100 spam-risk score with the exact fix for anything failing. No account, no test email to compose. It's the right first step when you're not sure why your email is going to spam.

• Email spam checker: the single spam-risk number with per-signal fixes
• DMARC checker: the record most domains get wrong
• SPF checker: whether your SPF includes every sender
• DKIM checker: whether your mail is actually signed
• IP reputation checker: whether your sending IP is blacklisted

Other alternatives, by use case

How they differ from Mail-Tester

Mail-Tester's strength is simplicity: one email in, one score out. Its limits are that the score is a single number, it tests the message rather than your sending infrastructure, and it won't tell you that your SPF is missing your ESP or that your IP is on a blocklist. The tools above fill those gaps: Inboxproof and MXToolbox inspect the DNS and reputation layer, Sender Score focuses on reputation, and GlockApps/InboxMonster test actual placement.

A practical workflow: run the free domain checks first (Inboxproof or MXToolbox) to fix authentication and reputation, then use a spam-score or inbox-placement tool to confirm a real message lands where you want it.

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