Email deliverability and testing tools for small business buyers
Asked as “email deliverability tool”, and as “inbox placement and email testing platform”, on behalf of a small B2B company. 62 first choices recorded across the direct, paraphrase, budget and scale prompts, fourteen models each. Added to the October 2026 Edition on October 4, 2026; its answers are read by the distilled judge (ai-indexes-judge-qwen3-14b-run3), not the claude-opus-5 judge of the earlier categories: how the two compare.
Standing · first-choice share
24%
Contested · Google Postmaster Tools 10%
24GlockApps10Google Postmaster Tools06MXToolbox60others
24% of first choices, contested.
By buyer segment
The same question asked on behalf of a different buyer. Each standing is computed within its segment; they sit side by side and are never added together.
The standing
Share is the count of first choices across the direct, paraphrase, budget and scale prompts, over all fourteen models, for a small B2B company. Ordered by share.
ProductFirst-choice shareNegative rateLabelsQuadrant
Show the two products at 0%, ordered by negative rate
Bars are the share of first choices, 0 to 100Every product with at least 10 labels here. Every product name links to its product page.
Google Postmaster Tools is made by Google, whose model Gemini 3.5 Flash is in the set. On the four share prompts that model made it the first choice one time of 4; the other thirteen models five times of 52. Lab treatment is defined on the method page; the row is marked, not excluded.
All twenty-eight head-to-head pages: the top eight products, each against each
GlockApps vs Mail-TesterGlockApps vs FolderlyGlockApps vs Microsoft SNDSGlockApps vs Validity EverestGoogle Postmaster Tools vs MailReachGoogle Postmaster Tools vs MXToolboxGoogle Postmaster Tools vs Mail-TesterGoogle Postmaster Tools vs FolderlyGoogle Postmaster Tools vs Microsoft SNDSGoogle Postmaster Tools vs Validity EverestMailReach vs MXToolboxMailReach vs Mail-TesterMailReach vs FolderlyMailReach vs Microsoft SNDSMailReach vs Validity EverestMXToolbox vs Mail-TesterMXToolbox vs FolderlyMXToolbox vs Microsoft SNDSMXToolbox vs Validity EverestMail-Tester vs FolderlyMail-Tester vs Microsoft SNDSMail-Tester vs Validity EverestFolderly vs Microsoft SNDSFolderly vs Validity EverestMicrosoft SNDS vs Validity Everest
Recommended versus criticized
Every product with at least 10 labels here, on both axes. The 30% line names a quadrant, not the verdict above: that one needs more than 40%.
Criticized challengerCriticized default
Negative label rate →
01G02
03
04
05
06
07
08M09
10W11
12
13
14
15Accepted challengerEndorsed leader
0%First-choice share → · lines at 30% share and 25% negative40%
Key
01GlockApps24%
GlockApps24%02Google Postmaster Tools10%
03MXToolbox6%
MXToolbox6%04ZeroBounce5%
ZeroBounce5%05Mail-Tester5%
Mail-Tester5%06MailReach5%
MailReach5%07Instantly5%
Instantly5%08Litmus5%
Litmus5%09Microsoft SNDS3%
10Mailtrap2%
Mailtrap2%11Warmbox2%
12Brevo2%
Brevo2%13Folderly2%
Folderly2%14Email on Acid0%
Email on Acid0%15Validity Everest0%
Validity Everest0%What they warned about
Zero of fourteen models held their first choice under the paraphrase. 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 and Muse Glimmer 30B changed. A high negative share on a product with few labels is a warning. A low share on a product with many labels is salience, not sentiment.
Litmus46%
13 of 28 labels negative · 8 of 14 models · 2 hard negative
“Litmus has effectively abandoned small businesses. They eliminated self-serve plans and now require enterprise sales conversations for all pricing.” Kimi K2, negative prompt
Validity Everest67%
12 of 18 labels negative · 7 of 14 models · 5 hard negative
“Enterprise platforms like **Validity Everest** (formerly Return Path) are designed for massive corporations... Why you should avoid them: These services are incredibly expensive” Gemini 3.5 Flash, negative prompt
GlockApps14%
7 of 51 labels negative · 6 of 14 models
“Services such as GlockApps or other inbox-placement testers can help compare results across test accounts, but seed accounts don’t behave like real subscribers.” GPT-6 Luna, negative prompt
Folderly31%
5 of 16 labels negative · 4 of 14 models · 2 hard negative
“the worst thing you can do is sign up for a high-ticket, $100+/month all-in-one deliverability platform (like Folderly or Validity Everest)” Gemini 3.5 Flash, budget prompt
What they cite
Citations exist only for the models that return a source list: fourteen of the fourteen in this edition, and all six flagship models on the expanded tier.
Sites the answers cite
74 of 84 answers in this category came back with a source list, from 14 of 14 models: citations where the model returns them, or the search results it consulted. 1032 links across 203 sites, every framing counted. Ranked by the number of answers carrying the site or page. None of the 252 answers across every segment cited this index's own page for the category.
vendor site · Amplemarket31 answers · 31 citations · 11 models
vendor site · Sender30 answers · 33 citations · 10 models
vendor site · Omnisend28 answers · 29 citations · 11 models
vendor site · MailerCheck27 answers · 31 citations · 10 models
vendor site · Mailtrap26 answers · 35 citations · 10 models
vendor site · MyEmailVerifier25 answers · 25 citations · 9 models
vendor site · MailReach20 answers · 27 citations · 12 models
vendor site · Saleshandy20 answers · 22 citations · 11 models
19 answers · 23 citations · 9 models
vendor site · Guideflow19 answers · 19 citations · 10 models
vendor site · Instantly18 answers · 23 citations · 10 models
vendor site · Folderly18 answers · 22 citations · 9 models
Pages the answers cite
The ten pages named in the most answers, by full address. A page here is one the models returned with a recommendation, not one the index endorses.
31 answers · 11 models
27 answers · 10 models
27 answers · 11 models
25 answers · 9 models
22 answers · 9 models
17 answers · 9 models
16 answers · 8 models
16 answers · 10 models
15 answers · 9 models
15 answers · 10 models
Search against answers
Each company's standing in the answers beside its site's footprint in Google search, one row a site: the products the models named on it with their shares, and the share they add up to; monthly searches on Google, and DataForSEO's estimate of AI search demand (modeled from search signals, directional, not a count of queries to any assistant), for the most-searched of the company's and its products' names (the name is in each row's hover text); estimated monthly organic visits to the site; and its best position in Google's top ten for “best email deliverability tool”, “email deliverability tool”. US estimates from DataForSEO and Google's Ads Transparency Center. A small company's site, or a mid-sized company's site for its flagship, is marked company; a product on a large parent's site (Google, Microsoft) has no site figures. A column with no figures for this category is left out, and an empty cell means none were seen, not none exist. Two measurements side by side: neither is read as the cause of the other.
| Company and products | Share | Own site cited | Name searches, Google | AI search demand, est. | Organic visits | Paid search a month, est. | Google ads, last 30 days | Best Google position |
|---|---|---|---|---|---|---|---|---|
| GlockApps glockapps.com | 24% | 148 | 1,600 | 3 | 8,647 | 1 | ||
| Google parent site Google Postmaster Tools 10% | 10% | 77 | 6,600 | 24 | ||||
| MXToolbox mxtoolbox.com | 6% | 71 | 60,500 | 126 | 453,570 | 18 | ||
| ZeroBounce zerobounce.net | 5% | 203 | 9,900 | 118 | 38,183 | $778 | 120 | |
| Mail-Tester mailtester.com | 5% | 51 | 5,400 | 93 | 3,496 | 4 | ||
| MailReach mailreach.co | 5% | 62 | 1,300 | 5 | 12,483 | 112 | ||
| Instantly instantly.ai | 5% | 106 | 74,000 | 87,944 | 59,881 | $986 | 17 | |
| Litmus litmus.com | 5% | 73 | 12,100 | 2,310 | 38,533 | 15 | ||
| Microsoft parent site Microsoft SNDS 3% | 3% | 41 | 2,240,000 | 403,136 | ||||
| Unspam unspam.email | 3% | 7 |
Google's top ten for the two searches hold 17 sites; 1 of them are among the sites the models cited here (folderly.com). The first result for “best email deliverability tool” is devopsschool.com.
How they answered
Six framings of the same buying question, each sent to every model in a fresh session with search on. One row per model, so a row shows whether it held its answer under rewording, what it named when cost was the constraint, and what it argued against. Computed from the raw judge labels.ShowHide
How they answered
Six framings of the same buying question, each sent to every model in a fresh session with search on. One row per model, so a row shows whether it held its answer under rewording, what it named when cost was the constraint, and what it argued against. Computed from the raw judge labels.
ShowHideModelDirect“What is the best email deliverability tool for a small B2B company?”Paraphrase“Which inbox placement and email testing platform would you recommend to a small business that sells to other businesses?”Comparative“What are the top email deliverability and testing tools for a small team and how do they differ?”Budget-constrained“What is the best email deliverability tool for a small company with a tight budget?”Scale-constrained“We are a 30 person company evaluating an email deliverability tool. What should we look at?”Negative“Which email deliverability and testing tools should a small business avoid or be cautious about?”
Claude Haiku 4.5no first choiceLitmusChangedMailtrapConstant Contactno first choiceagainst: GlockApps, Mail-Tester, Mailtrap, Send Forensics, Validity Everest
Three alternatives
250ok, Return Path, Validity EverestSix alternatives
Email on Acid, GlockApps, Litmus, Snov.io, Validity Everest, WarmboxTwo alternatives
Brevo, PostmarkGPT-5.4 miniLitmus, Validity EngageLitmusChangedLitmusSenderno first choicenothing named
One alternative
Mailgun OptimizeOne alternative
Mailgun OptimizeTwo alternatives
Email on Acid, Mailgun InspectTwo alternatives
Emailable, MailCleanupGemini 3.5 FlashInstantlyagainst: HubSpot, MailchimpGlockAppsChangedagainst: Litmus, Validity EverestGlockAppsGoogle Postmaster Tools, MXToolboxagainst: Folderly, Validity EverestGlockAppsagainst: ReturnPath, Validity Everestagainst: SpamAssassin, Validity Everest
Six alternatives
GlockApps, Inbox Radar, Lemwarm, Smartlead, TrulyInbox, ZeroBounceFive alternatives
Email on Acid, Mail-Tester, Saleshandy, Smartlead, Unspam.emailFive alternatives
MXToolbox, Mail-Tester, Mailtrap, TrulyInbox, ZeroBounceSix alternatives
Bouncer, GlockApps, Mail-Tester.com, Microsoft SNDS, Postmark DMARC Monitoring, TrulyInboxNine alternatives
Instantly, MXToolbox, MailerCheck, NeverBounce, Postmark DMARC, Smartlead, TrulyInbox, Warmy.io, ZeroBouncePerplexity SonarGlockAppsMailtrapChangedGlockApps, Google Postmaster ToolsGlockAppsno first choiceagainst: Instantly, Warmforge
Four alternatives
GetResponse, Google Postmaster Tools, MXToolbox, MailerCheckOne alternative
GlockAppsSix alternatives
Litmus, MXToolbox, Mailivery, Microsoft SNDS, Warmbox, WarmyFour alternatives
Brevo, Google Postmaster Tools, MXToolbox, SenderGrok 4.1 FastMailerCheckGlockAppsChangedagainst: Email on Acid, Litmus, MailReachGlockApps, Mail-Testeragainst: Validity EverestGoogle Postmaster Tools, MXToolbox, Mail-Tester.comZeroBounceagainst: CleanTalk, Constant Contact, Elastic Email SMTP, Folderly, Mailchimp, Mailwarm, SMTP.com, SendForensics, Validity Everest
Eight alternatives
ActiveCampaign, Google Postmaster Tools, MX Toolbox, Mail-Tester.com, Microsoft SNDS, Moosend, NeverBounce, ZeroBounceThree alternatives
Google Postmaster Tools, MX Toolbox, Mail-TesterThree alternatives
Email on Acid, Litmus, MailtrapFour alternatives
GlockApps, Microsoft SNDS, Sender Score, Yahoo Sender HubThree alternatives
GlockApps, Google Postmaster Tools, MailtrapMistral SmallFolderlyGlockAppsChangedEmail on Acid, Folderly, Inbox Inspector, MailerCheckagainst: LitmusMail-Tester, Unspamno first choiceagainst: Apollo.io, Benchmark Email, GlockApps, Kit, Litmus, Mail-Tester
Four alternatives
ActiveCampaign, Google Postmaster Tools, MXToolbox, WarmboxTwo alternatives
MailReach, Warmy.ioFour alternatives
Mailchimp, Mailslurp, NeverBounce, ZeroBounceTwo alternatives
Sequenzy, WarmboxDeepSeek V4 FlashMailReachGlockAppsChangedagainst: Litmus, Validity EverestEmail on Acid, GlockAppsagainst: LitmusMailercloudagainst: Everest, Folderly, MailchimpMailReachagainst: Folderly, Validity Everestagainst: Brevo, GetResponse, Mailchimp, Unspam.email
Eight alternatives
ActiveCampaign, Clearout, GlockApps, Google Postmaster Tools, MXToolbox, Mailgun, Warmbox, ZeroBounceTwo alternatives
Email on Acid, MailReachFour alternatives
MXToolbox, Mail-Tester.com, Mailtrap, Unspam.emailFour alternatives
Brevo, MailerLite, Mailtrap, MoosendSeven alternatives
Bouncer, Clearout, EasyDMARC, GlockApps, PowerDMARC, Sender, ZeroBounceLlama 4 Maverickno first choiceMailReachChangedno first choiceMail-Tester, Unspamno first choicenothing named
Eight alternatives
Amazon SES, Brevo, Elastic Email, Google Postmaster, MXToolbox, Microsoft SNDS, Sender, Yahoo Sender HubQwen 3.7 FlashGlockApps, ZeroBounceGlockAppsChangedGlockAppsBrevo, MailTester.com, MailerLiteagainst: Amazon SESno first choiceagainst: Folderly, GlockApps, Instantly, MailReach, Warmy
Two alternatives
Instantly, PostmarkTwo alternatives
Mail-Tester, MailReachFour alternatives
Folderly, Google Postmaster Tools, Mail-Tester, MailerCheckTwo alternatives
Gmass.co, Unspam.ioKimi K2InstantlyGlockAppsChangedagainst: Mail-TesterUnspam.emailWarmbox, Warmup Inboxno first choiceagainst: Brevo, Email on Acid, EmailDeliverability.com, GlockApps, Lemlist, Litmus, MXToolbox, dmarcian
Three alternatives
GlockApps, MailReach, SmartleadTwo alternatives
Unspam, ZeroBounce ONE™Four alternatives
GlockApps, Litmus, MailerCheck, MailtrapSix alternatives
Brevo, Google Postmaster Tools, MXToolbox, Mail-Tester, Mailjet, WarmforgeFive alternatives
Clearout, Google Postmaster Tools, MXToolbox, Mailtrap, ZeroBounceGLM 4.7 FlashXInstantlyMailGeniusChangedMailerCheckagainst: LitmusGoogle Postmaster Tools, MXToolbox, Mail-Tester, Microsoft SNDSEasyDMARC, GlockAppsagainst: Email on Acid, Litmus, Mailinator, Mailtrap
Five alternatives
Folderly, Kickbox, MXToolbox, Postmaster Tools, ZeroBounceThree alternatives
GlockApps, MailReach, MailtrapFour alternatives
Folderly, GlockApps, Mail-Tester, WarmboxTwo alternatives
Mailgun Optimize, Smartlead's Free Auth ToolsOne alternative
Google Postmaster ToolsMiniMax M2.5ZeroBounceGlockAppsChangedMailerCheckagainst: LitmusAmazon SESno first choiceagainst: EmailDeliverability.com, Litmus, Validity Everest
Two alternatives
ActiveCampaign, NeverBounceOne alternative
Email on AcidThree alternatives
Folderly, MailReach, WarmboxSix alternatives
Brevo, Check & Connect, GlockApps, Mail-Tester.com, Mailgun, PostmarkGPT-6 LunaGlockApps, Google Postmaster ToolsGlockAppsChangedGlockApps, Google Postmaster Toolsagainst: Validity EverestGoogle Postmaster Toolsagainst: GlockAppsno first choiceagainst: Google's Postmaster Toolsagainst: GlockApps
One alternative
LitmusThree alternatives
Litmus, Mailgun Inspect, Mailtrap Email SandboxOne alternative
Mail-TesterMuse Glimmer 30BPostmarkGlockAppsChangedagainst: LitmusEmail on Acid, GlockApps – Inbox Insightagainst: Litmus, MXToolbox, Mail-TesterGoogle Postmaster Tools, MXToolbox, Microsoft SNDS, Yahoo Sender Hubno first choiceagainst: EasyDMARC, EmailChecker.info, GlockApps, Validity Everest, ZeroBounce
Two alternatives
ActiveCampaign, FolderlyOne alternative
UnspamFive alternatives
Mailgun, Mailgun Optimize, Mailtrap, Postmark, Unspam.emailSix alternatives
EasyDMARC, Mail-Tester, PowerDMARC, Sender, Unspam.email, WarmforgeBold is the first choiceAlternatives are counted; the count opens them.What the answer argued against
The record
One row per call: the version string exactly as returned, whether the model searched, sources cited, and latency. Full answer text is in the free responses file. Download the record
Eighty-four rows: every prompt, every model, every answer.
| Prompt | Model | Version string | Time (UTC) | Searched | Sources | Latency |
|---|---|---|---|---|---|---|
| Direct recommendation | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-04 23:14 | no | 0 | 4 s |
| Direct recommendation | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-04 23:03 | yes | 3 | 4 s |
| Direct recommendation | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-05 00:46 | yes | 18 | 24 s |
| Direct recommendation | Perplexity Sonar | sonar | 2026-10-05 00:41 | yes | 17 | 3 s |
| Direct recommendation | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-04 23:45 | yes | 23 | 9 s |
| Direct recommendation | Mistral Small | mistral/mistral-small via mistral | 2026-10-05 00:52 | yes | 12 | 7 s |
| Direct recommendation | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-04 23:01 | yes | 22 | 24 s |
| Direct recommendation | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-05 00:48 | yes | 5 | 2 s |
| Direct recommendation | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-04 23:59 | no | 0 | 21 s |
| Direct recommendation | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-04 22:28 | yes | 15 | 26 s |
| Direct recommendation | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-05 01:03 | yes | 14 | 23 s |
| Direct recommendation | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-04 22:26 | yes | 13 | 29 s |
| Direct recommendation | GPT-6 Luna | gpt-6-luna | 2026-10-05 00:16 | yes | 2 | 11 s |
| Direct recommendation | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-05 00:12 | yes | 15 | 16 s |
| Paraphrase | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-04 22:38 | no | 0 | 5 s |
| Paraphrase | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-04 22:54 | yes | 2 | 4 s |
| Paraphrase | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-04 22:53 | yes | 14 | 22 s |
| Paraphrase | Perplexity Sonar | sonar | 2026-10-05 00:27 | yes | 18 | 2 s |
| Paraphrase | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-05 00:22 | yes | 24 | 9 s |
| Paraphrase | Mistral Small | mistral/mistral-small via mistral | 2026-10-05 00:08 | yes | 5 | 3 s |
| Paraphrase | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-04 22:54 | yes | 24 | 26 s |
| Paraphrase | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-05 00:35 | yes | 5 | 3 s |
| Paraphrase | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-05 00:29 | yes | 5 | 21 s |
| Paraphrase | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-04 23:24 | yes | 23 | 25 s |
| Paraphrase | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-05 00:27 | yes | 19 | 133 s |
| Paraphrase | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-04 22:33 | yes | 15 | 32 s |
| Paraphrase | GPT-6 Luna | gpt-6-luna | 2026-10-05 00:17 | yes | 4 | 26 s |
| Paraphrase | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-05 00:22 | yes | 14 | 15 s |
| Comparative | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-05 00:42 | yes | 17 | 11 s |
| Comparative | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-05 00:21 | yes | 4 | 7 s |
| Comparative | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-05 00:34 | yes | 13 | 29 s |
| Comparative | Perplexity Sonar | sonar | 2026-10-04 22:36 | yes | 18 | 6 s |
| Comparative | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-04 22:42 | yes | 23 | 10 s |
| Comparative | Mistral Small | mistral/mistral-small via mistral | 2026-10-04 23:59 | yes | 10 | 7 s |
| Comparative | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-05 00:40 | yes | 23 | 66 s |
| Comparative | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-05 00:27 | yes | 5 | 3 s |
| Comparative | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-05 01:02 | yes | 10 | 46 s |
| Comparative | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-05 00:18 | yes | 14 | 25 s |
| Comparative | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-04 23:43 | yes | 23 | 193 s |
| Comparative | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-04 22:31 | yes | 24 | 37 s |
| Comparative | GPT-6 Luna | gpt-6-luna | 2026-10-05 00:19 | yes | 6 | 28 s |
| Comparative | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-04 23:11 | yes | 24 | 27 s |
| Budget constrained | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-05 00:46 | yes | 9 | 7 s |
| Budget constrained | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-04 23:51 | yes | 3 | 3 s |
| Budget constrained | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-04 23:32 | yes | 8 | 20 s |
| Budget constrained | Perplexity Sonar | sonar | 2026-10-05 00:26 | yes | 17 | 3 s |
| Budget constrained | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-04 23:54 | yes | 20 | 8 s |
| Budget constrained | Mistral Small | mistral/mistral-small via mistral | 2026-10-04 23:53 | yes | 5 | 6 s |
| Budget constrained | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-05 00:03 | yes | 23 | 41 s |
| Budget constrained | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-05 00:41 | yes | 5 | 3 s |
| Budget constrained | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-04 22:30 | yes | 5 | 29 s |
| Budget constrained | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-05 00:47 | yes | 12 | 20 s |
| Budget constrained | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-05 00:01 | yes | 14 | 52 s |
| Budget constrained | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-04 23:07 | no | 0 | 31 s |
| Budget constrained | GPT-6 Luna | gpt-6-luna | 2026-10-05 00:43 | yes | 3 | 12 s |
| Budget constrained | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-04 23:13 | yes | 14 | 19 s |
| Scale constrained | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-04 22:36 | no | 0 | 6 s |
| Scale constrained | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-04 23:11 | no | 0 | 6 s |
| Scale constrained | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-05 00:02 | yes | 11 | 26 s |
| Scale constrained | Perplexity Sonar | sonar | 2026-10-05 00:53 | yes | 20 | 4 s |
| Scale constrained | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-04 23:36 | yes | 15 | 8 s |
| Scale constrained | Mistral Small | mistral/mistral-small via mistral | 2026-10-04 22:10 | no | 0 | 7 s |
| Scale constrained | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-04 22:22 | yes | 19 | 42 s |
| Scale constrained | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-04 22:38 | yes | 5 | 2 s |
| Scale constrained | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-05 00:59 | no | 0 | 27 s |
| Scale constrained | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-04 23:02 | yes | 13 | 38 s |
| Scale constrained | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-04 23:02 | yes | 14 | 27 s |
| Scale constrained | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-05 00:57 | no | 0 | 9 s |
| Scale constrained | GPT-6 Luna | gpt-6-luna | 2026-10-05 00:45 | yes | 2 | 22 s |
| Scale constrained | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-04 23:29 | no | 0 | 3 s |
| Negative framing | Claude Haiku 4.5 | claude-haiku-4-5-20251001 | 2026-10-04 22:57 | yes | 17 | 10 s |
| Negative framing | GPT-5.4 mini | gpt-5.4-mini-2026-03-17 | 2026-10-05 01:01 | yes | 5 | 5 s |
| Negative framing | Gemini 3.5 Flash | gemini-3.5-flash | 2026-10-04 23:13 | yes | 17 | 23 s |
| Negative framing | Perplexity Sonar | sonar | 2026-10-04 22:26 | yes | 20 | 4 s |
| Negative framing | Grok 4.1 Fast | spacexai/grok-4.1-fast-non-reasoning via vertex | 2026-10-04 22:18 | yes | 24 | 12 s |
| Negative framing | Mistral Small | mistral/mistral-small via mistral | 2026-10-05 01:01 | yes | 10 | 8 s |
| Negative framing | DeepSeek V4 Flash | deepseek/deepseek-v4-flash via deepinfra | 2026-10-04 23:29 | yes | 25 | 61 s |
| Negative framing | Llama 4 Maverick | meta/llama-4-maverick via bedrock | 2026-10-04 23:37 | yes | 10 | 3 s |
| Negative framing | Qwen 3.7 Flash | alibaba/qwen3.7-flash via alibaba | 2026-10-05 00:48 | yes | 23 | 42 s |
| Negative framing | Kimi K2 | moonshotai/kimi-k2 via novita | 2026-10-04 23:28 | yes | 24 | 49 s |
| Negative framing | GLM 4.7 FlashX | zai/glm-4.7-flashx via zai | 2026-10-05 00:40 | yes | 25 | 59 s |
| Negative framing | MiniMax M2.5 | minimax/minimax-m2.5 via minimax | 2026-10-04 22:45 | yes | 21 | 36 s |
| Negative framing | GPT-6 Luna | gpt-6-luna | 2026-10-04 22:56 | yes | 5 | 26 s |
| Negative framing | Muse Glimmer 30B | meta/muse-glimmer-30b via togetherai | 2026-10-04 22:44 | yes | 24 | 32 s |
Normalization in this category
Every judgment call made between the raw labels and the numbers above, listed so it is visible and reversible.
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Category-scoped readings
Validity read as Validity Everest
Validity (Everest) read as Validity Everest
Unresolved, counted raw
AWS SES
Check & Connect (by MXToolbox)
CleanTalk
DMARC Digests
Elastic Email
Elastic Email SMTP
EmailChecker.info
GlockApps – Inbox Insight
Gmass.co
Google's Postmaster Tools
InboxRadar
MailCleanup
MailTester.com
MailerLite Deliverability
Mailivery
Mailwarm
Postmark DMARC (Weekly Subscription)
Postmark DMARC Monitoring
ReturnPath
SMTP.com
SNDS
Send Forensics
Smartlead's Free Auth Tools
Testi@
Unspam.io
ZeroBounce ONE™
Discontinued, still offered
No shut-down product was recommended here.