Email deliverability and testing tools · November 2026 Edition
Litmus vs ZeroBounce
One of fourteen models named Litmus first on the direct prompt; two named ZeroBounce. Litmus was named by fourteen of the fourteen models and ZeroBounce by thirteen and Litmus carries 21 labels and ZeroBounce 28, so the shares are not directly comparable.
Named in one category this edition.
Named in four categories this edition.
First-choice share6%4%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate10%14%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#3#4A position in a field of 19; printed, not drawn.
Labels2128A count; the two differ.
The two percentage rows are drawn on one 0 to 100 track, Litmus reading right to left. Rank and label count are printed, not drawn.GlockApps was named alongside these two in twelve of the fourteen direct answers. GlockApps vs Litmus · GlockApps vs ZeroBounce · Google Postmaster Tools vs Litmus
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.
LitmusFirst choices, of fourteen modelsZeroBounce
Direct121 against ZeroBounce
Paraphrase202 against Litmus
Comparative10
Budget-constrained001 against ZeroBounce
Scale-constrained00
Negative002 against ZeroBounce
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.
Every model, every framing
The eighty-four answers behind the chart above, one cell each: where Litmus and ZeroBounce 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 | |
Litmus ZeroBounce first choice named as an alternative argued againstblank: not namedEach cell is one answer, Litmus on the left and ZeroBounce on the right.The direct prompt
The plain question, one answer per model, grouped by where Litmus and ZeroBounce stood in it.
Litmus first, ZeroBounce an alternative
1 of 14 modelsZeroBounce 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
ZeroBounce first, Litmus not the choice
2 of 14 modelsLitmus was named in the answer but not as the choice, or not at all.Qwen 3.7 FlashGlockApps, ZeroBounce alternatives: Kickbox, NeverBounce, Red Sift OnDMARC, SendForensics, Suped, Validity Everest
MiniMax M2.5HubSpot Sales Hub, ZeroBounce alternatives: Copper, GlockApps, MXToolbox
Neither was the first choice, one was named
2 of 14 modelsThe answer put something else first and named one of the two as an alternative.Perplexity SonarGlockApps alternatives: EasyDMARC, Google Postmaster Tools, MailReach, Microsoft SNDS, NeverBounce, Validity Everest, ZeroBounce, dmarcian
Mistral SmallAllegrow, Validity Everest alternatives: Litmus
Neither was named
9 of 14 modelsThe answer made no first choice from these two in this category.Claude Haiku 4.5Warmy alternatives: Act-On, GlockApps, MailReach, Mailtrap Email Marketing
Gemini 3.5 FlashGlockApps alternatives: Folderly, Google Postmaster Tools, Mailgun Optimize, Mailtrap Email Sandbox, Microsoft Smart Network Data Services (SNDS) / Microsoft 365 Admin Insights
Grok 4.20GlockApps alternatives: Allegrow, Validity Everest
DeepSeek V4 FlashHubSpot Sales Hub alternatives: GlockApps, Klaviyo, Lemlist, Mailgun, Outreach, Salesloft, SendGrid
Llama 4 MaverickGlockApps alternatives: MailReach, Validity Everest
Kimi K2Allegrow alternatives: GlockApps, MailReach
GLM 4.7 FlashXGlockApps alternatives: Allegrow, MailReach
GPT-6 LunaGlockApps alternatives: Google Postmaster Tools, Validity Engage
Muse Glimmer 30BGlockApps, MailGenius alternatives: Allegrow, Amplemarket
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
Mid-marketThe figures above
Enterprise
Level: the same share of first choices.
Litmus2%#8 of 17ZeroBounce2%#9 of 17What 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
What the models said about ZeroBounce
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Two of two in this category shown.
“Address-verification services such as ZeroBounce, Kickbox, or comparable vendors: treat results as risk estimates, not proof of consent” Perplexity Sonar · negative prompt · soft negative
“"Valid" emails bouncing (both soft and hard bounces); precision issues with certain domains” Kimi K2 · negative prompt · soft negative
Also compared
GlockApps vs LitmusGlockApps vs ZeroBounceGoogle Postmaster Tools vs LitmusGoogle Postmaster Tools vs ZeroBounceLitmus vs MXToolboxLitmus vs MailReachLitmus vs Validity EverestLitmus vs Mail-TesterZeroBounce vs MXToolboxZeroBounce vs MailReachZeroBounce vs Validity EverestZeroBounce 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.