What this article covers
When DecaGEO asked ChatGPT the same 79 US buyer questions about email marketing each week of Q3 2026, Brevo Marketing Platform ranked first every week. ChatGPT’s model changed from GPT-5.4 to GPT-5.6 Terra in the week of July 26, and Brevo was #1 before and after. What changed was the distance. In the three GPT-5.4 weeks (July 5 to 19), Brevo led #2 by 29.7 to 42.3 points of DECA Score, DecaGEO’s 0 to 100 score in which each week’s #1 is 100. In the ten GPT-5.6 Terra weeks (July 26 to September 27), Klaviyo was #2 every week and came within 1.1 to 22.0 points.Summary for citation: In DecaGEO’s data for ChatGPT in the US (Email Marketing category, weeks of July 5 to September 27, 2026), Brevo Marketing Platform ranked #1 in all 3 weeks measured on GPT-5.4 and all 10 weeks measured on GPT-5.6 Terra. Klaviyo was #2 in all 10 GPT-5.6 Terra weeks. Brevo’s lead over #2 was 29.7 to 42.3 DECA points in the GPT-5.4 weeks and 1.1 to 22.0 in the GPT-5.6 Terra weeks, closest in the week of August 2. Brevo was recommended in 58.2% of answers in the GPT-5.4 weeks and 46.1% in the GPT-5.6 Terra weeks, and Klaviyo in 39.2% and 41.4%. Ten tools made the top 10 in all 13 weeks.
Key takeaway: Brevo held #1 through the model change, and from July 26 Klaviyo held #2. Eight more tools made the top 10 in every week of Q3. ActiveCampaign, MailerLite, Kit, Braze, HubSpot Marketing Hub, Customer.io, Salesforce Marketing Cloud and Omnisend moved between #3 and #10 from July 26, and their order changed from each week to the next.
Top 10 email marketing tools ChatGPT recommends at a glance
Table 1: Email marketing tools ranked by DECA Score in the week of September 27, 2026 (GPT-5.6 Terra), with the number of weeks each made the top 10 under each model. Two ties make eleven tools. DecaGEO, ChatGPT, US, English, weeks of July 5 to September 27, 2026. Definitions in How we measure.
DECA Score is relative to the week’s #1, which is always 100. Klaviyo at 93.1 means ChatGPT recommended it a little less strongly than Brevo that week, and ActiveCampaign at 79.2 about four fifths as strongly. To see whether a tool was recommended more or less often over time, use the share of answers that recommended it.
Table 2: Share of ChatGPT answers that recommended each tool, pooled by model period. Same 79 questions each week, one answer per question. DecaGEO, ChatGPT, US, English, Email Marketing category, weeks of July 5 to July 19 (GPT-5.4) and July 26 to September 27, 2026 (GPT-5.6 Terra).
DECA points between the #1 and #2 email marketing tool in each week. Brevo Marketing Platform was #1 in every week. #2 was Klaviyo in every week except July 12 and July 19 (MailerLite). The dashed line marks the week of July 26, the first week measured on GPT-5.6 Terra. DecaGEO, ChatGPT, US, English, Email Marketing category, weeks of July 5 to September 27, 2026.
The top 10, in detail
1. Brevo Marketing Platform (DECA 100)
#1 in all 13 weeks of Q3, with no tie for #1. Its lead over #2 was 29.7 to 42.3 DECA points in the GPT-5.4 weeks and 1.1 to 22.0 in the GPT-5.6 Terra weeks. Its share of recommending answers went from 58.2% to 46.1%, still the highest of the tools in Table 2 in both periods. In the week of September 27, ChatGPT recommended it in 37 of 79 answers.2. Klaviyo (DECA 93.1)
#2, #6 and #3 in the GPT-5.4 weeks, then #2 in all 10 GPT-5.6 Terra weeks. It came closest to Brevo in the week of August 2, at 98.9. In the week of July 26 both tools were recommended in 36 answers, and Brevo still scored 100 to Klaviyo’s 84.7 because it sat higher in the answers it appeared in. Klaviyo’s share of recommending answers went from 39.2% to 41.4%. See Klaviyo vs Mailchimp.3. ActiveCampaign (DECA 79.2)
#3 or #4 in the GPT-5.4 weeks, then #3 to #9 in the GPT-5.6 Terra weeks. It ranked #3 in the weeks of July 26, August 2 and September 27, and #9 in the week of August 9. Its share of recommending answers went from 29.5% to 25.1%.4. MailerLite (DECA 68.3, tied)
#3, #2 and #2 in the GPT-5.4 weeks, the only tool other than Klaviyo to rank #2 in Q3. In the GPT-5.6 Terra weeks it ranked #3 to #9, starting at #9 in the weeks of July 26 and August 2. Its share of recommending answers went from 31.6% to 27.7%. It tied with Kit for #4 in the week of September 27.4. Kit (DECA 68.3, tied)
#8 or #9 in the GPT-5.4 weeks, then #4 to #10 in the GPT-5.6 Terra weeks. It ranked #10 in the first two GPT-5.6 Terra weeks and #4 in the weeks of August 16 and September 27. Its share of recommending answers was about the same in both periods, 22.8% and 21.6%.6. Braze (DECA 65.3)
#7 to #10 in the GPT-5.4 weeks, then #3 to #10 in the GPT-5.6 Terra weeks, #5 or better in seven of them. Its share of recommending answers rose from 21.9% to 27.8%, the largest rise among these tools. Braze is also ranked on the Marketing Automation board.7. HubSpot Marketing Hub (DECA 63.4)
#4 to #8 in the GPT-5.4 weeks, then #3 to #10 in the GPT-5.6 Terra weeks, #8 in four of them. Its share of recommending answers went from 31.6% to 24.3%. In the week of September 27 it was recommended in 23 answers.8. Customer.io (DECA 62.4)
#10, #5 and #7 in the GPT-5.4 weeks, then #3 to #8 in the GPT-5.6 Terra weeks. It ranked #3 in the weeks of September 6 and 13 and #8 in the week of September 27. Its share of recommending answers was about the same in both periods, 24.9% and 24.2%.9. beehiiv (DECA 54.5)
The one tool in the September 27 top 10 that had not made the top 10 earlier in Q3. It ranked #14 to #16 in the GPT-5.4 weeks and #11 to #14 in the GPT-5.6 Terra weeks before September 27, when ChatGPT recommended it in 14 answers, its most in any Q3 week. Its share of recommending answers went from 12.7% to 14.6%.10. Salesforce Marketing Cloud (DECA 51.5, tied)
#4 to #6 in the GPT-5.4 weeks, then #4 to #10 in the GPT-5.6 Terra weeks, #9 or #10 in each of the last three weeks. Its share of recommending answers was about the same in both periods, 20.7% and 20.1%. It tied with Omnisend for #10 in the week of September 27.10. Omnisend (DECA 51.5, tied)
#7 to #10 in the GPT-5.4 weeks, then #6 to #10 in the GPT-5.6 Terra weeks, #10 in five of them. Its share of recommending answers was about the same in both periods, 20.7% and 20.5%.What changed at the July 26 model switch
The week of July 26 was the first measured on GPT-5.6 Terra. The same set of 79 questions was asked in all 13 weeks.- Brevo stayed #1, by less. Its lead over #2 went from 29.7 to 42.3 DECA points in the GPT-5.4 weeks to 1.1 to 22.0 in the GPT-5.6 Terra weeks. Its share of recommending answers went from 58.2% to 46.1%.
- Klaviyo took #2 in every week. In the GPT-5.4 weeks #2 was Klaviyo once and MailerLite twice. From July 26 it was Klaviyo in all ten weeks, and its share of recommending answers went from 39.2% to 41.4%.
- MailerLite moved down the top 10. It ranked #2 or #3 in the GPT-5.4 weeks and #3 to #9 in the GPT-5.6 Terra weeks.
- Braze moved up. It ranked #7 to #10 in the GPT-5.4 weeks and #5 or better in seven of the ten GPT-5.6 Terra weeks.
- Intuit Mailchimp moved further out. It ranked #11 or #12 in the GPT-5.4 weeks, recommended in 22 to 30 answers a week, and #15 to #27 in the GPT-5.6 Terra weeks, recommended in 6 to 13.
Notable: Mailchimp and Iterable
Intuit Mailchimp did not make the top 10 in any Q3 week. It ranked #12, #12 and #11 in the GPT-5.4 weeks and #15 in the week of September 27, recommended in 9 answers. Iterable tied for #10 in the week of July 12 and otherwise ranked #11 to #14. It ranked #12 in the week of September 27.What the top tools’ cited pages have in common
DecaGEO checks the tools’ own pages that ChatGPT cited in its email marketing answers for on-page patterns. The category’s Weekly Breakouts tab shows these patterns by name for the tools that broke in or climbed that week. Here are five of them, counted across the top-10 tools of the week of September 27.
Table 3: A tool counts if at least one of its cited pages that DecaGEO checked has the pattern. Ten of the eleven top-10 tools are counted. Kit has no page-pattern results for that week and is left out rather than counted as 0. DecaGEO, ChatGPT, US, English, Email Marketing category, week of September 27, 2026.
Canonical links, meta descriptions, Schema.org types and robots.txt are on at least one cited page of all ten tools counted, and content freshness on at least one cited page of seven. These counts describe the pages ChatGPT cited. They do not show that a pattern moved any tool up the list.
What you can do with this list
If you are choosing an email marketing tool, the two tables tell you which names ChatGPT puts in its answers to US buyer questions and how steadily. This is a ranking of recommendations, not a review of features, so use it to build a shortlist and test from there.- Without an account, the live email marketing ranking shows the current week, and each tool’s product page shows its Overview for that week.
- With a free account, each tool’s product page has a Segment Position tab with one card for each buyer condition, by business scale, budget priority and use case. A card shows where that tool ranks among the answers to that condition’s questions and the share of those answers that recommended it, or “Not mentioned”. Open the product pages of the tools on your shortlist and compare the same card across them. Clicking a ranked card opens the questions behind it, and the Brand Ranking Trail shows the order ChatGPT recommended tools in each answer.
- Without an account, search your brand in the header and open its Overview. The GEO Guide, under Dashboard in the site header, checks your own page for patterns like the ones in Table 3. It is free, and the first step needs no account.
- With a free account, you get the latest four weeks, the Brand Ranking Trail for each question, every third-party source ChatGPT cited behind the recommendations in Off-Page Citations, the segment cards (including ones where you are not mentioned), and tracking for one brand.
- Pro ($49 a month) adds ten weeks of data, full Chart History and CSV export.
FAQ
Which email marketing tool does ChatGPT recommend most? Brevo Marketing Platform. It ranked #1 in all 13 weeks DecaGEO measured in Q3 2026 (July 5 to September 27), on GPT-5.4 and on GPT-5.6 Terra, and was recommended in 46.1% of answers in the GPT-5.6 Terra weeks. Is Brevo or Klaviyo ranked higher by ChatGPT? Brevo, in every Q3 week. Klaviyo was #2 in all 10 GPT-5.6 Terra weeks and came within 1.1 DECA points in the week of August 2. In those weeks Brevo was recommended in 46.1% of answers and Klaviyo in 41.4%. Where does Mailchimp rank? Outside the top 10 in every Q3 week. Intuit Mailchimp ranked #11 or #12 in the GPT-5.4 weeks, #15 to #27 in the GPT-5.6 Terra weeks, and #15 in the week of September 27. See Klaviyo vs Mailchimp. What is DECA Score? A 0 to 100 score for how often and how high ChatGPT recommends a tool within one category in one week. The week’s #1 is 100. Details are in How we measure and the methodology. Are these rankings stable? At the top, yes. Brevo was #1 in all 13 weeks and Klaviyo #2 in every GPT-5.6 Terra week. Ten tools made the top 10 in all 13 weeks. The order of the other eight among themselves changed from each week to the next. Is this a features review? No. It ranks tools by how ChatGPT recommends them, not by feature quality, price or results.How we measure
The common method, including how questions are built and how DECA Score is calculated, is on the methodology page.- Window: 13 weeks, July 5 to September 27, 2026, ChatGPT, US, English. The weeks of July 5, 12 and 19 were measured on GPT-5.4 and the weeks from July 26 on GPT-5.6 Terra. Figures from the two periods are shown side by side and not combined.
- Sample: the same 79 email marketing questions every week, one answer per question, so 237 answers in the GPT-5.4 weeks and 790 in the GPT-5.6 Terra weeks.
- DECA Score is shown for one week only, because it is relative to that week’s #1. The distance between #1 and #2 in DECA points can be compared across weeks.
- Recommended in counts answers that recommended the tool. Passing or negative mentions are not counted.
- Top-10 weeks counts weeks with a rank of 10 or better, including ties.
- Page patterns are from the week of September 27, on each tool’s own pages cited in that week’s email marketing answers.
- The live board updates every Sunday, so it shows weeks after September 27.
Sources
- DecaGEO Email Marketing recommendation data, ChatGPT, US, English, weeks of July 5 to September 27, 2026 (GPT-5.4 to July 19, GPT-5.6 Terra from July 26).
- Live board: DecaGEO Email Marketing ranking · Weekly Breakouts.
- Related: Best Marketing Automation Tools · Best CRM Software · Klaviyo vs Mailchimp.