Google Postmaster Tools vs Mail-Tester
Zero of fourteen models named Google Postmaster Tools first on the direct prompt; zero named Mail-Tester. Google Postmaster Tools was named by thirteen of the fourteen models and Mail-Tester by eleven and Google Postmaster Tools carries 34 labels and Mail-Tester 27, so the shares are not directly comparable.
Google Postmaster Tools
accepted challengerBy Google, Mountain View, California, United States, founded 1998. Named in one category this edition.
Named in one category this edition.
Share is the count of first choices across the direct, paraphrase, budget and scale prompts over all fourteen models, for a mid-market B2B company; rank is within the category; every quote names the model and the prompt it came from. Both figures come from the email deliverability and testing tools page.
By framing
Across every category in the November 2026 Edition, Google Postmaster Tools and Mail-Tester were named in the same answer forty-four times, of the 84 answers naming Google Postmaster Tools and the 70 naming Mail-Tester. In those answers Mail-Tester took the first choice two times and Google Postmaster Tools seven.
Every model, every framing
| Model | DirectGP | ParaphraseGP | ComparativeGP | Budget-constrainedGP | Scale-constrainedGP | NegativeGP |
|---|---|---|---|---|---|---|
| Claude Haiku 4.5 | GP | GP | | |||
| GPT-5.4 mini | GP | |||||
| Gemini 3.5 Flash | GP | | GP | | ||
| Perplexity Sonar | GP | GP | GP | GP | GP | |
| Grok 4.20 | GP | GP | GP | |||
| Mistral Small | GP | GP | | |||
| DeepSeek V4 Flash | GP | GP | GP | GP | ||
| Llama 4 Maverick | ||||||
| Qwen 3.7 Flash | GP | GP | ||||
| Kimi K2 | GP | | ||||
| GLM 4.7 FlashX | GP | GP | ||||
| MiniMax M2.5 | GP | |||||
| GPT-6 Luna | GP | GP | GP | |||
| Muse Glimmer 30B | GP | GP | GP | GP | |
Mail-TesterGP first choiceGP named as an alternativeGP argued againstblank: not namedEach cell is one answer, Google Postmaster Tools on the left and Mail-Tester on the right.The direct prompt
Neither was the first choice, one was named
3 of 14 modelsThe answer put something else first and named one of the two as an alternative.Neither was named
11 of 14 modelsThe answer made no first choice from these two in this category.Bold names in an answer are the products the judge labeled a first choice; a model naming several gives each of them that label. The full answer text for every row is in the record.
By buyer segment
Mail-Tester7%#4 of 15Mail-Tester2%#8 of 19Mail-Tester0%#– of 17What the models said about Google Postmaster Tools
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Five of six in this category shown.
“tools such as Google Postmaster Tools are valuable, but Gmail data can be delayed or unavailable at low volume” Perplexity Sonar · negative prompt · soft negative
“valuable if you send enough to Gmail to get data, but it's not a full inbox placement tester” GPT-5.4 mini · comparative prompt · soft negative
“For maximum budget efficiency, start with Google Postmaster Tools and MXToolbox, which are both free” Claude Haiku 4.5 · budget prompt · first choice
“Best first step for monitoring Gmail delivery, spam reports, authentication, and delivery errors.” GPT-6 Luna · budget prompt · first choice
“If you are starting out, begin with Google Postmaster Tools (free, essential for Gmail data)” Qwen 3.7 Flash · comparative prompt · first choice
What the models said about Mail-Tester
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Mail-Tester does one thing well: it runs your email through SpamAssassin and checks your SPF, DKIM, and DMARC records. That's useful. It's also not enough.” Muse Glimmer 30B · negative prompt · soft negative
“Email "spam score" checkers such as Mail-Tester: good for finding technical problems, but a favorable score does not predict inbox placement.” Perplexity Sonar · negative prompt · soft negative
“Use these only as a diagnostic aid, not as a primary decision-making tool.” DeepSeek V4 Flash · negative prompt · soft negative
“Start with Unspam's free tier or Mail-Tester if you need immediate, low-cost testing.” Kimi K2 · budget prompt · first choice
“Instant spam score (0–10) based on content, authentication, and reputation. No signup needed for basic use.” Grok 4.20 · comparative prompt · alternative
“Cited as a best deliverability testing tool in 2026 with a free spam score, real inbox-placement testing” Muse Glimmer 30B · comparative prompt · alternative
Comparisons are drawn for the top eight products in each category, each against each. The output is the models' output; nothing here is a recommendation by the index.