GlockApps vs MailTester

GlockApps helps marketers and businesses check email deliverability and investigate placement problems before sending campaigns. Inbox Insight shows whether test messages reach inboxes, spam folders, or subfolders at different providers, and checks them against SpamAssassin, Barracuda, Microsoft Exchange Online Protection, Proofpoint, and a Google filter. Reputation tools check IPs and domains against blocklists and report sender scores and placement by IP. Content analysis covers message size, images, and links, with an HTML compatibility checker. DMARC Analytics collects reports, tracks sending sources, and retains reports for a year. Uptime Monitor checks IPs, SPF, DKIM, DMARC, HTTP, TLS, and TCP, with checks configurable as often as every minute. The API supports automated testing, result retrieval, and client management by projects and folders on all plans, including free. GlockApps runs on the web and through an API. Its free plan includes two spam test credits; paid plans start at $59 a month, billed annually at $708.

MailTester checks why email may reach spam and returns a deliverability score out of 10. To run a test, generate a disposable address, send the message there and receive a report in seconds. Scoring starts at 10, subtracts points for detected issues, and explains penalties with suggested fixes. Authentication checks include SPF, DKIM, DMARC, domain alignment, reverse DNS and forward-confirmed reverse DNS. Sending IPs are checked against Spamhaus, SpamCop, Barracuda and other DNS blocklists. Content analysis covers HTML, text-to-image ratio, links, subject, List-Unsubscribe and Message-ID. Rspamd supplies a spam score and triggered rules. Newsletter checks include one-click List-Unsubscribe under RFC 8058, message size and text-image ratio. MailTester offers web, API and self-hosted platforms. Its API creates test addresses and reads report status and scores as JSON. The free plan costs nothing, needs no account and provides 25+ checks per test.