Email deliverability and testing tools · November 2026 Edition
GlockApps vs Litmus
Eight of fourteen models named GlockApps first on the direct prompt; one named Litmus. Both were named by all fourteen models and GlockApps carries 57 labels and Litmus 21, so the shares are not directly comparable.
Named in one category this edition.
Named in one category this edition.
First-choice share38%6%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate9%10%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#1#3A position in a field of 19; printed, not drawn.
Labels5721A 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 ZeroBounce · 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 modelsLitmus
Direct81
Paraphrase1022 against Litmus
Comparative91
Budget-constrained001 against GlockApps
Scale-constrained10
Negative204 against GlockApps
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 November 2026 Edition, GlockApps and Litmus were named in the same answer fifty-nine times, of the 161 answers naming GlockApps and the 68 naming Litmus. In those answers Litmus took the first choice five times and GlockApps twenty-five.
Every model, every framing
The eighty-four answers behind the chart above, one cell each: where GlockApps and Litmus 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 4.20 | | | | | | |
| 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 Litmus first choice named as an alternative argued againstblank: not namedEach cell is one answer, GlockApps on the left and Litmus on the right.The direct prompt
The plain question, one answer per model, grouped by where GlockApps and Litmus stood in it.
GlockApps first, Litmus not the choice
8 of 14 modelsLitmus was named in the answer but not as the choice, or not at all.Gemini 3.5 FlashGlockApps alternatives: Folderly, Google Postmaster Tools, Mailgun Optimize, Mailtrap Email Sandbox, Microsoft Smart Network Data Services (SNDS) / Microsoft 365 Admin Insights
Perplexity SonarGlockApps alternatives: EasyDMARC, Google Postmaster Tools, MailReach, Microsoft SNDS, NeverBounce, Validity Everest, ZeroBounce, dmarcian
Grok 4.20GlockApps alternatives: Allegrow, Validity Everest
Llama 4 MaverickGlockApps alternatives: MailReach, Validity Everest
Qwen 3.7 FlashGlockApps, ZeroBounce alternatives: Kickbox, NeverBounce, Red Sift OnDMARC, SendForensics, Suped, Validity Everest
GLM 4.7 FlashXGlockApps alternatives: Allegrow, MailReach
GPT-6 LunaGlockApps alternatives: Google Postmaster Tools, Validity Engage
Muse Glimmer 30BGlockApps, MailGenius alternatives: Allegrow, Amplemarket
Litmus first, GlockApps not the choice
1 of 14 modelsGlockApps was named in the answer but not as the choice, or not at all.GPT-5.4 miniLitmus alternatives: Brevo, HubSpot, Salesforce/Marketing Cloud, ZeroBounce
Neither was the first choice, one was named
5 of 14 modelsThe answer put something else first and named one of the two as an alternative.Claude Haiku 4.5Warmy alternatives: Act-On, GlockApps, MailReach, Mailtrap Email Marketing
Mistral SmallAllegrow, Validity Everest alternatives: Litmus
DeepSeek V4 FlashHubSpot Sales Hub alternatives: GlockApps, Klaviyo, Lemlist, Mailgun, Outreach, Salesloft, SendGrid
Kimi K2Allegrow alternatives: GlockApps, MailReach
MiniMax M2.5HubSpot Sales Hub, ZeroBounce alternatives: Copper, GlockApps, 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 twenty-three points.
GlockApps25%#1 of 15Litmus2%#11 of 15Mid-marketThe figures above
GlockApps leads by thirty-two points.
GlockApps38%#1 of 19Litmus6%#3 of 19Enterprise
What 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.
“Seed-list placement testers such as GlockApps, Unspam, or similar tools: useful for directional comparisons, but test accounts do not behave like real subscribers” Perplexity Sonar · negative prompt · soft negative
“GlockApps primarily uses syntax and DNS checks, which can miss subtle delivery issues like greylisting or role account filters.” Muse Glimmer 30B · negative prompt · soft negative
“Tools like GlockApps, Mail-Tester, and similar seed-list platforms have significant limitations” DeepSeek V4 Flash · negative prompt · soft negative
“The best email deliverability tool for a mid-market B2B company is GlockApps, as it offers the best all-in-one diagnostics for mid-market teams.” Llama 4 Maverick · direct prompt · first choice
“GlockApps is cited as the most comprehensive email deliverability platform for testing where mail lands across Gmail, Outlook, Yahoo and others” Muse Glimmer 30B · direct prompt · first choice
“Top-rated for scheduled inbox placement testing, spam scoring, and heatmap reports... Often praised as the best balance of features and cost.” Grok 4.20 · comparative prompt · first choice
What the models said about Litmus
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Five of six in this category shown.
“Caveat: These are primarily design/rendering testing tools. Their inbox placement features are secondary.” Kimi K2 · paraphrase prompt · soft negative
“Overkill (and pricey) for mid-sized teams; better for enterprises” DeepSeek V4 Flash · paraphrase prompt · soft negative
“I'd generally recommend Litmus if your priority is email testing, QA, rendering previews, and team workflow” GPT-5.4 mini · paraphrase prompt · first choice
“Best Overall for Marketing Workflow & Outlook Testing: Litmus” Gemini 3.5 Flash · paraphrase prompt · first choice
“Marketing team sending campaigns: Litmus + GlockApps” GPT-5.4 mini · comparative prompt · first choice
Also compared
GlockApps vs Google Postmaster ToolsGlockApps vs ZeroBounceGlockApps vs MXToolboxGlockApps vs MailReachGlockApps vs Validity EverestGlockApps vs Mail-TesterGoogle Postmaster Tools vs LitmusLitmus vs ZeroBounceLitmus vs MXToolboxLitmus vs MailReachLitmus vs Validity EverestLitmus vs Mail-TesterAll 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.