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Email deliverability and testing tools · November 2026 Edition

Litmus vs MXToolbox

One of fourteen models named Litmus first on the direct prompt; zero named MXToolbox. Litmus was named by fourteen of the fourteen models and MXToolbox by thirteen and Litmus carries 21 labels and MXToolbox 32, so the shares are not directly comparable.

Litmus

accepted challenger

Named in one category this edition.

MXToolbox

accepted challenger

Named in one category this edition.

First-choice share6%2%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate10%6%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#3#5A position in a field of 19; printed, not drawn.
Labels2132A 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 MXToolbox · 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 modelsMXToolbox
Direct10
Paraphrase202 against Litmus
Comparative11
Budget-constrained01
Scale-constrained00
Negative012 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, Litmus and MXToolbox were named in the same answer twenty-five times, of the 68 answers naming Litmus and the 80 naming MXToolbox. In those answers MXToolbox took the first choice two times and Litmus two.

Every model, every framing

The eighty-four answers behind the chart above, one cell each: where Litmus and MXToolbox stood in it.
ModelDirectParaphraseComparativeBudget-constrainedScale-constrainedNegative
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 MXToolbox first choice named as an alternative argued againstblank: not namedEach cell is one answer, Litmus on the left and MXToolbox on the right.

The direct prompt

The plain question, one answer per model, grouped by where Litmus and MXToolbox stood in it.

Litmus first, MXToolbox not the choice

1 of 14 modelsMXToolbox 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

2 of 14 modelsThe answer put something else first and named one of the two as an alternative.
Mistral SmallAllegrow, Validity Everest alternatives: Litmus
MiniMax M2.5HubSpot Sales Hub, ZeroBounce alternatives: Copper, GlockApps, MXToolbox

Neither was named

11 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
Perplexity SonarGlockApps alternatives: EasyDMARC, Google Postmaster Tools, MailReach, Microsoft SNDS, NeverBounce, Validity Everest, ZeroBounce, dmarcian
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
Qwen 3.7 FlashGlockApps, ZeroBounce alternatives: Kickbox, NeverBounce, Red Sift OnDMARC, SendForensics, Suped, 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
MXToolbox leads by four points.
MXToolbox5%#6 of 15
Litmus2%#11 of 15
The full small business standing →
Mid-marketThe figures above
The order flips: Litmus leads at mid-market.
Litmus6%#3 of 19
MXToolbox2%#5 of 19
The full mid-market standing →
Enterprise
Litmus leads by two points.
Litmus2%#8 of 17
MXToolbox0%#16 of 17
The full enterprise standing →

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

What 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
Also compared

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.