Synthflow vs Vapi:Which is more popular?
In September 2026, Vapi had more branded searches than Synthflow among AI voice agents worldwide. Vapi had about 18,100 branded searches, while Synthflow had 4,400. Vapi made up 15.5% of all AI voice agent searches we track, and Synthflow accounted for 3.8%. When we asked ChatGPT and Google AI Overviews about AI voice agents, Synthflow and Vapi each appeared in four of the five answers. Vapi was mentioned before Synthflow in four out of five answers.
Who do people search for more?
Vapi, about 4 searches for every 1 for Synthflow
Who does AI mention more?
Both were mentioned in 4 of 5 answers.
Who does AI recommend more?
Vapi, named ahead of Synthflow in 4 of 5 answers
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Top AI voice agents in ChatGPT and Google AI Overviews
In three ChatGPT questions and two Google AI Overviews, Synthflow was mentioned in four out of five: in two of the three ChatGPT answers and in both Google AI Overviews. Vapi was mentioned in four out of five: in all three ChatGPT answers and in one of the two Google AI Overviews. Vapi was listed before Synthflow in four out of five answers.
Most recommended by AI
Brands get a higher ranking if they are mentioned earlier in the answers.
Mentioned by AI
Each dot is one answer, filled in when that answer mentions the brand.
Retell AI5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers
Bland AI5 of 5Named in 3 of 3 ChatGPT answersNamed in 2 of 2 Google answers- Vapi4 of 5Named in 3 of 3 ChatGPT answersNamed in 1 of 2 Google answers
Synthflow4 of 5Named in 2 of 3 ChatGPT answersNamed in 2 of 2 Google answers
Voiceflow2 of 5Named in 1 of 3 ChatGPT answersNamed in 1 of 2 Google answers
See every answer about AI voice agents
5 answers
Asked ChatGPT
“Which AI voice agent platform should I use?”
Asked ChatGPT
“What are the best AI voice agent platforms?”
Asked ChatGPT
“What's the best AI voice agent platform for customer calls?”
Searched Google, AI Overview
“ai voice agent platforms”
Searched Google, AI Overview
“ai phone agent”
Brands are shown in the order each answer named them. The survey took place in the United States on October 20, 2026.
Is Synthflow or Vapi more popular in search?
This chart shows how often people search Google for Synthflow and Vapi by name. Each line represents a brand's share of searches for all five AI voice agents we track, month by month, from English-language searches worldwide.
Share of searches by month for Vapi, Synthflow. The figures are in the table below the chart.
View monthly share of searches table
| Month | Retell AI | Vapi | Voiceflow | Bland AI | Synthflow |
|---|---|---|---|---|---|
| Oct 2025 | 39.5% | 17.7% | 26.4% | 8.5% | 7.9% |
| Nov 2025 | 40.1% | 18% | 26.9% | 8.5% | 6.6% |
| Dec 2025 | 45% | 16.5% | 24.6% | 7.8% | 6% |
| Jan 2026 | 46.3% | 16.9% | 20.7% | 9.9% | 6.2% |
| Feb 2026 | 45.9% | 16.8% | 20.5% | 11.7% | 5% |
| Mar 2026 | 43.8% | 19.6% | 19.6% | 11.2% | 5.9% |
| Apr 2026 | 45.2% | 20.2% | 20.2% | 9.5% | 4.9% |
| May 2026 | 44.8% | 24.5% | 16.4% | 9.3% | 4.9% |
| Jun 2026 | 44.3% | 19.8% | 19.8% | 11.3% | 4.8% |
| Jul 2026 | 45.9% | 20.6% | 16.8% | 11.7% | 5% |
| Aug 2026 | 54.3% | 16.3% | 16.3% | 9.2% | 4% |
| Sep 2026 | 51.9% | 15.5% | 15.5% | 13.3% | 3.8% |
How has the Synthflow and Vapi comparison changed over the last 12 months?
3 findings
- Vapi was ahead of Synthflow in every measured month of the 12 months ending September 2026.
- Across the 12 months ending September 2026, Synthflow’s share of searches among AI voice agents worldwide moved from 7.9% to 3.8%, and its estimated monthly branded searches moved from 12.1K to 4.4K.
- Across the 12 months ending September 2026, Vapi’s share of searches among AI voice agents worldwide moved from 17.7% to 15.5%, and its estimated monthly branded searches moved from 27.1K to 18.1K.
How did search popularity change for AI voice agents worldwide in September 2026?
2 changes
In September 2026, Vapi lost share of searches among AI voice agents worldwide, from 16.3% to 15.5%.
Estimated monthly branded searches for Synthflow worldwide fell 63.6% over 12 measured months, from 12.1K to 4.4K in September 2026.
How are branded searches counted?
2 search terms
Brandwave collects information about searches that people make online using Synthflow’s and Vapi’s names. When viewed over time, estimated search volumes for these branded terms can be used to understand whether interest in the brands is growing, holding steady, or fading.
Other head-to-heads among AI voice agents
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