Email deliverability and testing tools · November 2026 Edition
ZeroBounce vs Mail-Tester
Two of fourteen models named ZeroBounce first on the direct prompt; zero named Mail-Tester. ZeroBounce was named by thirteen of the fourteen models and Mail-Tester by eleven and ZeroBounce carries 28 labels and Mail-Tester 27, so the shares are not directly comparable.
Named in four categories this edition.
Named in one category this edition.
First-choice share4%2%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate14%19%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#4#8A position in a field of 19; printed, not drawn.
Labels2827A count; the two differ.
The two percentage rows are drawn on one 0 to 100 track, ZeroBounce 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 ZeroBounce · GlockApps vs Mail-Tester · Google Postmaster Tools vs ZeroBounce
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.
ZeroBounceFirst choices, of fourteen modelsMail-Tester
Direct201 against ZeroBounce
Paraphrase00
Comparative00
Budget-constrained011 against ZeroBounce
Scale-constrained00
Negative002 against ZeroBounce · 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.
Every model, every framing
The eighty-four answers behind the chart above, one cell each: where ZeroBounce 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 4.20 | | | | |||
| 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 | | | | |
ZeroBounce Mail-Tester first choice named as an alternative argued againstblank: not namedEach cell is one answer, ZeroBounce on the left and Mail-Tester on the right.The direct prompt
The plain question, one answer per model, grouped by where ZeroBounce and Mail-Tester stood in it.
ZeroBounce first, Mail-Tester not the choice
2 of 14 modelsMail-Tester 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.GPT-5.4 miniLitmus alternatives: Brevo, HubSpot, Salesforce/Marketing Cloud, ZeroBounce
Perplexity SonarGlockApps alternatives: EasyDMARC, Google Postmaster Tools, MailReach, Microsoft SNDS, NeverBounce, Validity Everest, ZeroBounce, dmarcian
Neither was named
10 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
Mistral SmallAllegrow, Validity Everest alternatives: Litmus
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
Mail-Tester leads by seven points.
Mail-Tester7%#4 of 15ZeroBounce0%#12 of 15Mid-marketThe figures above
The order flips: ZeroBounce leads at mid-market.
ZeroBounce4%#4 of 19Mail-Tester2%#8 of 19Enterprise
ZeroBounce leads by two points.
ZeroBounce2%#9 of 17Mail-Tester0%#– of 17What 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
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
Also compared
GlockApps vs ZeroBounceGlockApps vs Mail-TesterGoogle Postmaster Tools vs ZeroBounceGoogle Postmaster Tools vs Mail-TesterLitmus vs ZeroBounceLitmus vs Mail-TesterZeroBounce vs MXToolboxZeroBounce vs MailReachZeroBounce vs Validity EverestMXToolbox vs Mail-TesterMailReach vs Mail-TesterValidity Everest 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.