SMS and WhatsApp marketing platforms · November 2026 Edition
Customer.io vs Klaviyo SMS
Seven of fourteen models named Customer.io first on the direct prompt; zero named Klaviyo SMS. Customer.io was named by eleven of the fourteen models and Klaviyo SMS by fourteen and Customer.io carries 14 labels and Klaviyo SMS 30, so the shares are not directly comparable.
Named in twelve categories this edition.
By Klaviyo, Boston, United States, founded 2012. Named in two categories this edition.
First-choice share19%5%Of first choices across the direct, paraphrase, budget and scale prompts, 0 to 100.
Negative rate0%13%Negative labels as a share of the product's labels, 0 to 100.
Rank in category#1#5A position in a field of 20; printed, not drawn.
Labels1430A count; the two differ.
The two percentage rows are drawn on one 0 to 100 track, Customer.io reading right to left. Rank and label count are printed, not drawn.Customer.io vs Brevo · Customer.io vs SimpleTexting · Customer.io vs Twilio Programmable Messaging
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 SMS and WhatsApp marketing platforms page.
By framing
How many of the fourteen models made each the first choice, per way of asking, and how many argued against it.
Customer.ioFirst choices, of fourteen modelsKlaviyo SMS
Direct701 against Klaviyo SMS
Paraphrase40
Comparative04
Budget-constrained03
Scale-constrained00
Negative003 against Klaviyo SMS
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 Customer.io and Klaviyo SMS 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 | | | | | |
Customer.io Klaviyo SMS first choice named as an alternative argued againstblank: not namedEach cell is one answer, Customer.io on the left and Klaviyo SMS on the right.The direct prompt
The plain question, one answer per model, grouped by where Customer.io and Klaviyo SMS stood in it.
Customer.io first, Klaviyo SMS not the choice
7 of 14 modelsKlaviyo SMS was named in the answer but not as the choice, or not at all.Claude Haiku 4.5Customer.io alternatives: ActiveCampaign, Heymarket, Salesmsg, SlickText, Vero
Perplexity SonarCustomer.io alternatives: ActiveCampaign, SlickText
Grok 4.20Customer.io alternatives: ActiveCampaign, Braze, Iterable
DeepSeek V4 FlashCustomer.io alternatives: ActiveCampaign, HubSpot Marketing Hub, Twilio Programmable Messaging
Llama 4 MaverickCustomer.io
MiniMax M2.5Customer.io, OneSignal alternatives: Brevo, Sinch, SlickText
Muse Glimmer 30BCustomer.io alternatives: Salesmsg
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.Gemini 3.5 FlashSalesmsg alternatives: Customer.io, Mogli, Sakari, TextUs
Qwen 3.7 FlashHubSpot Marketing Hub alternatives: Customer.io, Marigold
Neither was named
5 of 14 modelsThe answer made no first choice from these two in this category.GPT-5.4 miniTwilio Programmable Messaging alternatives: Braze, SimpleTexting
Mistral SmallAttentive, Twilio Programmable Messaging alternatives: Insider
Kimi K2Salesmsg alternatives: EZ Texting, SimpleTexting
GLM 4.7 FlashXVibes alternatives: SimpleTexting, SlickText, TrueDialog
GPT-6 LunaMogli, Sakari alternatives: HubSpot's native SMS add-on
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
Klaviyo SMS leads by three points.
Klaviyo SMS3%#9 of 17Customer.io0%#– of 17Mid-marketThe figures above
The order flips: Customer.io leads at mid-market.
Customer.io19%#1 of 20Klaviyo SMS5%#5 of 20Enterprise
Level: the same share of first choices.
Customer.io0%#– of 14Klaviyo SMS0%#13 of 14What the models said about Customer.io
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Two of two in this category shown.
“The consensus for mid-market B2B SMS is Customer.io... with Customer.io as the best-in-class upgrade for SMS-centric, event-driven B2B programs.” Muse Glimmer 30B · paraphrase prompt · first choice
“For SMS: Customer.io is the top pick for mid-sized B2B companies due to its scalability, automation, and developer-friendly approach.” Mistral Small · paraphrase prompt · first choice
What the models said about Klaviyo SMS
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Many buyers report frustration with high costs and missing features, especially with platforms like Attentive, Postscript, and Klaviyo SMS.” Mistral Small · negative prompt · soft negative
“with Klaviyo SMS beside them — draw complaints about cost, getting data in, building flows, support, missing features and attribution” Muse Glimmer 30B · negative prompt · soft negative
“Billing traps around "active profiles"... Strong overall (4+ stars), but watch billing closely.” Grok 4.20 · negative prompt · soft negative
“The best SMS marketing platform for a company with a limited budget is Klaviyo, which offers a starting price of $20/mo” Llama 4 Maverick · budget prompt · first choice
“Unbeatable for e-commerce — it unifies customer data with SMS/WhatsApp campaigns and automations” DeepSeek V4 Flash · comparative prompt · first choice
“For North American E-Commerce Brands: Choose Klaviyo (if unifying email and SMS)” Gemini 3.5 Flash · comparative prompt · first choice
Also compared
Customer.io vs BrevoCustomer.io vs SimpleTextingCustomer.io vs Twilio Programmable MessagingCustomer.io vs Respond.ioCustomer.io vs OmnisendCustomer.io vs WATIBrevo vs Klaviyo SMSSimpleTexting vs Klaviyo SMSTwilio Programmable Messaging vs Klaviyo SMSKlaviyo SMS vs Respond.ioKlaviyo SMS vs OmnisendKlaviyo SMS vs WATIAll twenty-eight head-to-head pages and the full SMS & WhatsApp 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.