Mail-Tester vs GlockApps

Mail-Tester and GlockApps are both used to check an email before it goes out, and they are often mentioned together. They measure different things. Mail-Tester gives a single message a technical score out of ten. GlockApps shows where a message actually lands across many mailbox providers. Understanding that difference will stop you from drawing the wrong conclusion from a good score.

At a glance

• Mail-Tester is best for a fast, free technical check of one email. Occasional manual tests need no account, and paid test packs start at $5.
• GlockApps is best for ongoing inbox placement testing and monitoring. It has a free tier with two tests, and paid plans from $59 a month.

Where Mail-Tester is strong

Mail-Tester is as simple as a testing tool can be. The site gives you a temporary address, you send your email to it, and a few seconds later you get a score out of ten with an explanation.

The report checks whether SPF, DKIM and DMARC pass, runs the message through SpamAssassin, looks up your sending IP and domain on common blocklists, and flags problems such as broken links, missing unsubscribe headers or badly formed HTML. For someone setting up a new sending domain, it is the quickest way to confirm that the basics are in place.

Occasional tests are free through the website. Heavier users can buy packs, starting at $5 for 10 tests, or a subscription from $10 a month for 50 tests. Paid accounts add an API, white-label reports and a history of results.

Where GlockApps is strong

GlockApps answers a harder question. It sends your message to real seed mailboxes at Gmail, Outlook, Yahoo and many other providers, then reports the folder each copy landed in. You see inbox, spam, promotions and missing percentages by provider, along with authentication results and filter verdicts.

That reflects real filtering decisions and not a rules-based estimate. It also lets you compare. You can test two subject lines, two sending domains or two email service providers and see which places better.

The wider platform adds DMARC analytics, uptime monitoring and IP reputation alerts. Essential costs $59 a month with 360 test credits, and Growth costs $99 a month with 1,080.

Key differences

• What is measured. Mail-Tester scores technical quality. GlockApps reports actual folder placement.
• Providers covered. Mail-Tester tests against its own server. GlockApps tests against many real mailbox providers.
• Cost. Mail-Tester is free for occasional use. GlockApps is a monthly subscription, with a small free tier.
• Monitoring. GlockApps includes DMARC and blocklist monitoring. Mail-Tester is a point-in-time check.
• Effort. Mail-Tester takes seconds. GlockApps needs a seed list send and a few minutes for results.

Deliverability notes

A score of ten out of ten on Mail-Tester does not mean your email will reach the inbox. It means the message is technically sound. Gmail and Microsoft decide placement mostly on sender reputation and recipient engagement, which no content checker can see. Plenty of perfectly formed emails go to spam because the domain has a history of complaints.

The reverse also holds. A low Mail-Tester score almost always points to something you should fix, such as failed authentication or a blocklisted IP.

Seed testing has limits too. Seed mailboxes do not behave like real subscribers, so treat results as directional. The most reliable picture comes from combining tools: a technical check before sending, placement tests when something changes, and Google Postmaster Tools plus your own engagement data for the long-term trend.

Which should you choose?

• Choose Mail-Tester to verify a new setup, check a template, or confirm that authentication is working.
• Choose GlockApps if you send regularly at volume and need to know where your mail lands at each provider.

Most serious senders use both. They do different jobs, and one of them is free.

Pricing was checked on each vendor's website in October 2026 and changes often. Confirm current rates before you buy.