Email deliverability and testing tools · October 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 twelve of the fourteen models and Validity Everest by twelve and MXToolbox carries 31 labels and Validity Everest 27, so the shares are not directly comparable.
Named in two categories this edition.
Named in one category this edition.
First-choice share5%3%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate10%26%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#4#8A position in a field of 12; printed, not drawn.
Labels3127A count; the two differ.
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 thirteen 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
Direct013 against Validity Everest
Paraphrase004 against Validity Everest
Comparative00
Budget-constrained30
Scale-constrained01
Negative003 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 October 2026 Edition, MXToolbox and Validity Everest were named in the same answer twenty-seven times, of the 72 answers naming MXToolbox and the 92 naming Validity Everest. In those answers Validity Everest took the first choice seven 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 4.1 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 | | | | |
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.GPT-6 LunaValidity Everest alternatives: GlockApps
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.Grok 4.1 FastGlockApps alternatives: MailReach, Validity Everest, Warmy.io
DeepSeek V4 FlashMailReach alternatives: GlockApps, Google Postmaster Tools, MXToolbox
MiniMax M2.5Folderly, Mailtrap alternatives: EasyDMARC, MXToolbox
Muse Glimmer 30BGlockApps alternatives: MailReach, Validity Everest
Neither was named
9 of 14 modelsThe answer made no first choice from these two in this category.Claude Haiku 4.5InboxArmy, MailBrace alternatives: Folderly, GlockApps, HubSpot, Mailsoftly
GPT-5.4 miniMailgun Optimize alternatives: GlockApps
Gemini 3.5 FlashAllegrow, GlockApps alternatives: Mailgun Optimize, ZeroBounce
Perplexity SonarGlockApps alternatives: Amplemarket, MailReach, NeverBounce
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
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 six points.
MXToolbox6%#3 of 15Validity Everest0%#15 of 15Mid-marketThe figures above
MXToolbox leads by two points.
MXToolbox5%#4 of 12Validity Everest3%#8 of 12Enterprise
The order flips: Validity Everest leads at enterprise.
Validity Everest45%#1 of 14MXToolbox0%#14 of 14What the models said about MXToolbox
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of seven in this category shown.
“MxToolbox is an infrastructure diagnostic tool, not a campaign email testing tool... best used only for specific DNS and infrastructure checks, not comprehensive campaign testing.” Claude Haiku 4.5 · negative prompt · hard negative
“Free tools like Mail Tester and MxToolbox handle basic checks but lack the depth for production workflows.” Muse Glimmer 30B · negative prompt · soft negative
“lack depth for production-scale testing, inbox placement simulation, or ongoing monitoring” Grok 4.1 Fast · negative prompt · soft negative
“Best free option: Stack Google Postmaster Tools, Microsoft SNDS, Yahoo Sender Hub, MXToolbox, Mail Tester, AboutMyEmail, and Sender Hub.” GLM 4.7 FlashX · budget prompt · first choice
“free monitoring stack with Google Postmaster Tools, Microsoft SNDS, MXToolbox, and Yahoo Sender Hub” Perplexity Sonar · budget prompt · first choice
“Start with free tools → Google Postmaster Tools + MXToolbox + Mail-Tester free tier” Kimi K2 · budget 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.
“its pricing often starts at $20,000 to $65,000/year, making it massive overkill and too expensive for most mid-sized operations” Gemini 3.5 Flash · paraphrase prompt · soft negative
“enterprise suites like *Validity Everest* (which can cost upward of $15,000/year) to be too complex and cost-prohibitive” Gemini 3.5 Flash · direct prompt · soft negative
“The gold standard for enterprise, but likely overkill for mid-sized companies on both features and budget.” DeepSeek V4 Flash · paraphrase prompt · soft negative
“The gold standard for larger mid-market and enterprise brands. Extremely deep seed-testing network and comprehensive reputation monitoring, though highly priced.” Gemini 3.5 Flash · scale prompt · first choice
“My default pick: Validity Everest” GPT-6 Luna · direct prompt · first choice
“Everest is the largest and most robust platform in the space... generally cost-prohibitive for SMBs.” Gemini 3.5 Flash · comparative prompt · alternative
Also compared
GlockApps vs MXToolboxGlockApps vs Validity EverestGoogle Postmaster Tools vs MXToolboxGoogle Postmaster Tools vs Validity EverestMailReach vs MXToolboxMailReach vs Validity EverestMXToolbox vs Mail-TesterMXToolbox vs FolderlyMXToolbox vs Microsoft SNDSMail-Tester vs Validity EverestFolderly vs Validity EverestMicrosoft SNDS 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.