Mail-Tester

Mail-Tester gives you a disposable test inbox address. Send your campaign (subject + HTML/text body) to that address, then open Mail-Tester to get a comprehensive report. The report includes an overall “spam score” and breaks down issues across multiple categories: spam-assassin rules triggered, missing or misconfigured authentication (SPF/DKIM/DMARC), blacklisted IP/domain checks, suspicious links, image/text ratio, suspicious phrases, MIME issues, and more. It also shows how major spam filters may react and gives practical remediation tips (e.g., remove certain words, fix DKIM signing, reduce image-only content). It’s extremely convenient for pre-send QA because it evaluates the raw email exactly as delivered (including headers). Free to use for single tests; you can repeat tests as needed.