Email deliverability and testing tools · October 2026 Edition
GlockApps vs Mail-Tester
Nine of fourteen models named GlockApps first on the direct prompt; zero named Mail-Tester. GlockApps was named by fourteen of the fourteen models and Mail-Tester by eleven and GlockApps carries 57 labels and Mail-Tester 20, so the shares are not directly comparable.
Named in one category this edition.
Named in one category this edition.
First-choice share34%5%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate7%25%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#1#5A position in a field of 12; printed, not drawn.
Labels5720A count; the two differ.
The two percentage rows are drawn on one 0 to 100 track, GlockApps reading right to left. Rank and label count are printed, not drawn.GlockApps vs Google Postmaster Tools · GlockApps vs MailReach · GlockApps vs MXToolbox
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
How many of the fourteen models made each the first choice, per way of asking, and how many argued against it.
GlockAppsFirst choices, of fourteen modelsMail-Tester
Direct90
Paraphrase100
Comparative120
Budget-constrained133 against GlockApps
Scale-constrained00
Negative301 against GlockApps · 5 against Mail-Tester
Bars are first choices, 0 to 14 each sideModels that argued againstA model can name both, so the two sides of a row do not sum to fourteen.
Across every category in the October 2026 Edition, GlockApps and Mail-Tester were named in the same answer thirty-eight times, of the 153 answers naming GlockApps and the 52 naming Mail-Tester. In those answers Mail-Tester took the first choice three times and GlockApps seventeen.
Every model, every framing
The eighty-four answers behind the chart above, one cell each: where GlockApps and Mail-Tester stood in it.
| Model | Direct | Paraphrase | Comparative | Budget-constrained | Scale-constrained | Negative |
|---|---|---|---|---|---|---|
| Claude Haiku 4.5 | | | | | ||
| GPT-5.4 mini | | | | |||
| Gemini 3.5 Flash | | | | | | |
| Perplexity Sonar | | |||||
| Grok 4.1 Fast | | | | | | |
| Mistral Small | | | | | ||
| DeepSeek V4 Flash | | | | | | |
| Llama 4 Maverick | | | ||||
| Qwen 3.7 Flash | | | | | ||
| Kimi K2 | | | | | | |
| GLM 4.7 FlashX | | | | | | |
| MiniMax M2.5 | | | ||||
| GPT-6 Luna | | | | | ||
| Muse Glimmer 30B | | | | | |
GlockApps Mail-Tester first choice named as an alternative argued againstblank: not namedEach cell is one answer, GlockApps on the left and Mail-Tester on the right.The direct prompt
The plain question, one answer per model, grouped by where GlockApps and Mail-Tester stood in it.
GlockApps first, Mail-Tester not the choice
9 of 14 modelsMail-Tester was named in the answer but not as the choice, or not at all.Gemini 3.5 FlashAllegrow, GlockApps alternatives: Mailgun Optimize, ZeroBounce
Perplexity SonarGlockApps alternatives: Amplemarket, MailReach, NeverBounce
Grok 4.1 FastGlockApps alternatives: MailReach, Validity Everest, Warmy.io
Mistral SmallFolderly, GlockApps alternatives: MailReach, Zoho CRM
Llama 4 MaverickGlockApps
Qwen 3.7 FlashGlockApps alternatives: 250ok, Instantly, Kickbox, Lemlist, Valimail, ZeroBounce
Kimi K2GlockApps, Instantly alternatives: HubSpot Sales Hub, MailReach
GLM 4.7 FlashXGlockApps, MailReach alternatives: Folderly, Warmy
Muse Glimmer 30BGlockApps alternatives: MailReach, Validity Everest
Neither was the first choice, one was named
4 of 14 modelsThe answer put something else first and named one of the two as an alternative.Claude Haiku 4.5InboxArmy, MailBrace alternatives: Folderly, GlockApps, HubSpot, Mailsoftly
GPT-5.4 miniMailgun Optimize alternatives: GlockApps
DeepSeek V4 FlashMailReach alternatives: GlockApps, Google Postmaster Tools, MXToolbox
GPT-6 LunaValidity Everest alternatives: GlockApps
Neither was named
1 of 14 modelsThe answer made no first choice from these two in this category.MiniMax M2.5Folderly, Mailtrap alternatives: EasyDMARC, MXToolbox
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
The same question asked on behalf of a different buyer. Each standing is computed within its segment and they are never added together. The figures above are the mid-market standing, which is the one the category orders by.
Small business
GlockApps leads by nineteen points.
GlockApps24%#1 of 15Mail-Tester5%#5 of 15Mid-marketThe figures above
GlockApps leads by twenty-nine points.
GlockApps34%#1 of 12Mail-Tester5%#5 of 12Enterprise
GlockApps leads by two points.
GlockApps2%#5 of 14Mail-Tester0%#– of 14What the models said about GlockApps
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“GlockApps became popular for one specific capability... Test credits do not roll over... stops at telling you what is wrong.” Muse Glimmer 30B · negative prompt · soft negative
“a fraction of what enterprise tools like GlockApps ($85+/month) or ZeroBounce ($99/month) would cost” DeepSeek V4 Flash · budget prompt · soft negative
“Good for deeper testing, but pricier; consider only if you have repeated deliverability issues” GLM 4.7 FlashX · budget prompt · soft negative
“For most mid-sized B2B companies, GlockApps offers the best balance of comprehensive diagnostics, B2B-appropriate seed lists, and reasonable pricing.” Claude Haiku 4.5 · paraphrase prompt · first choice
“the best choice is usually GlockApps if you want the strongest balance of inbox placement testing, DMARC monitoring, and mid-market pricing” Perplexity Sonar · direct prompt · first choice
“For most mid-sized B2B companies, GlockApps is the best choice due to its depth of inbox placement testing and deliverability diagnostics.” Mistral Small · paraphrase 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 scores against a single seed address, so it can't tell you where your email lands across a multi-ISP seed network” Claude Haiku 4.5 · negative prompt · hard negative
“These are inaccurate and misleading... do not base business decisions on them.” DeepSeek V4 Flash · negative prompt · hard negative
“Avoid: Relying solely on these web-based scores. They are useful for a quick syntax check but should not be your primary deliverability testing tool.” GLM 4.7 FlashX · negative prompt · soft negative
“Mail-Tester for occasional pre-send checks of a message and its sending setup. It allows up to 3 free tests per day.” GPT-6 Luna · budget prompt · first choice
“The best email deliverability tool for a company with a limited budget is Mail-Tester or Unspam for pre-send testing” Llama 4 Maverick · budget prompt · first choice
“Start with free tools → Google Postmaster Tools + MXToolbox + Mail-Tester free tier” Kimi K2 · budget prompt · first choice
Also compared
GlockApps vs Google Postmaster ToolsGlockApps vs MailReachGlockApps vs MXToolboxGlockApps vs FolderlyGlockApps vs Microsoft SNDSGlockApps vs Validity EverestGoogle Postmaster Tools vs Mail-TesterMailReach vs Mail-TesterMXToolbox vs Mail-TesterMail-Tester vs FolderlyMail-Tester vs Microsoft SNDSMail-Tester vs Validity EverestAll twenty-eight head-to-head pages and the full email deliverability standing
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.