Email deliverability and testing tools · November 2026 Edition
MXToolbox vs Validity Everest
Zero of fourteen models named MXToolbox first on the direct prompt; one named Validity Everest. MXToolbox was named by thirteen of the fourteen models and Validity Everest by twelve and both carry 32 labels, so the shares below are directly comparable.
Named in one category this edition.
Named in one category this edition.
First-choice share2%2%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate6%22%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#5#7A position in a field of 19; printed, not drawn.
Labels3232Equal, which is what makes the shares comparable.
The two percentage rows are drawn on one 0 to 100 track, MXToolbox 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 MXToolbox · GlockApps vs Validity Everest · Google Postmaster Tools 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.
MXToolboxFirst choices, of fourteen modelsValidity Everest
Direct011 against Validity Everest
Paraphrase003 against Validity Everest
Comparative11
Budget-constrained102 against Validity Everest
Scale-constrained001 against Validity Everest
Negative112 against MXToolbox
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, MXToolbox and Validity Everest were named in the same answer twenty-eight times, of the 80 answers naming MXToolbox and the 82 naming Validity Everest. In those answers Validity Everest took the first choice ten times and MXToolbox two.
Every model, every framing
The eighty-four answers behind the chart above, one cell each: where MXToolbox and Validity Everest 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 | | | | |
MXToolbox Validity Everest first choice named as an alternative argued againstblank: not namedEach cell is one answer, MXToolbox on the left and Validity Everest on the right.The direct prompt
The plain question, one answer per model, grouped by where MXToolbox and Validity Everest stood in it.
Validity Everest first, MXToolbox not the choice
1 of 14 modelsMXToolbox was named in the answer but not as the choice, or not at all.Mistral SmallAllegrow, Validity Everest alternatives: Litmus
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.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
MiniMax M2.5HubSpot Sales Hub, ZeroBounce alternatives: Copper, GlockApps, MXToolbox
Neither was named
8 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
GPT-5.4 miniLitmus alternatives: Brevo, HubSpot, Salesforce/Marketing Cloud, ZeroBounce
Gemini 3.5 FlashGlockApps alternatives: Folderly, Google Postmaster Tools, Mailgun Optimize, Mailtrap Email Sandbox, Microsoft Smart Network Data Services (SNDS) / Microsoft 365 Admin Insights
DeepSeek V4 FlashHubSpot Sales Hub alternatives: GlockApps, Klaviyo, Lemlist, Mailgun, Outreach, Salesloft, SendGrid
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
MXToolbox leads by five points.
MXToolbox5%#6 of 15Validity Everest0%#– of 15Mid-marketThe figures above
Level: the same share of first choices.
MXToolbox2%#5 of 19Validity Everest2%#7 of 19Enterprise
The order flips: Validity Everest leads at enterprise.
Validity Everest46%#1 of 17MXToolbox0%#16 of 17What the models said about MXToolbox
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Five of six in this category shown.
“Blocklist-only monitors such as MXToolbox or Heatwave: a clean result does not mean good deliverability” Perplexity Sonar · negative prompt · soft negative
“basic free blocklist checkers (in isolation) ... Over-reliance can give false confidence.” Grok 4.20 · negative prompt · soft negative
“start with Google Postmaster Tools and MXToolbox, which are both free and cover the most common starting points” Claude Haiku 4.5 · budget prompt · first choice
“Use free tools (Google Postmaster, MXToolbox, Microsoft SNDS) for monitoring” MiniMax M2.5 · negative prompt · first choice
“Start with free tools like MXToolbox and Google Postmaster for diagnostics.” Grok 4.20 · comparative prompt · first choice
What the models said about Validity Everest
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Unnecessary enterprise tools (Validity Everest, etc.) unless you're at scale.” GLM 4.7 FlashX · budget prompt · hard negative
“High price tag (typically starting at $5,000–$15,000+/year) and demo-first sales cycles, which can be overkill for mid-sized teams.” Gemini 3.5 Flash · direct prompt · soft negative
“rather than paying for an expensive all-in-one suite (like Validity Everest or Inbox Monster, which can cost hundreds per month)” Gemini 3.5 Flash · budget prompt · soft negative
“Validity Everest and Allegrow are the top choices due to their scalability, B2B focus, and comprehensive feature sets” Mistral Small · direct prompt · first choice
“For marketers: Start with GlockApps or Validity Everest for deliverability” Mistral Small · comparative prompt · first choice
“Use a combination: GlockApps or Validity (for placement testing)” Grok 4.20 · negative prompt · first choice
Also compared
GlockApps vs MXToolboxGlockApps vs Validity EverestGoogle Postmaster Tools vs MXToolboxGoogle Postmaster Tools vs Validity EverestLitmus vs MXToolboxLitmus vs Validity EverestZeroBounce vs MXToolboxZeroBounce vs Validity EverestMXToolbox vs MailReachMXToolbox vs Mail-TesterMailReach vs Validity EverestValidity 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.