Retell AI vs Synthflow
Four of fourteen models named Retell AI first on the direct prompt; one named Synthflow. Retell AI was named by fourteen of the fourteen models and Synthflow by twelve and Retell AI carries 55 labels and Synthflow 36, so the shares are not directly comparable.
Named in one category this edition.
Named in one category this edition.
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 AI voice agents page.
By framing
Retell AIFirst choices, of fourteen modelsSynthflow
Across every category in the November 2026 Edition, Retell AI and Synthflow were named in the same answer eighty-eight times, of the 152 answers naming Retell AI and the 100 naming Synthflow. In those answers Synthflow took the first choice sixteen times and Retell AI seventeen.
Every model, every framing
| 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 | | | | |
Retell AI Synthflow first choice named as an alternative argued againstblank: not namedEach cell is one answer, Retell AI on the left and Synthflow on the right.The direct prompt
Retell AI first, Synthflow an alternative
4 of 14 modelsSynthflow was named in the answer but not as the choice, or not at all.Synthflow first, Retell AI not the choice
1 of 14 modelsRetell AI was named in the answer but not as the choice, or not at all.Neither was the first choice, one was named
7 of 14 modelsThe answer put something else first and named one of the two as an alternative.Neither was named
2 of 14 modelsThe answer made no first choice from these two in this category.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
Retell AI15%#1 of 11Synthflow6%#5 of 11Retell AI17%#2 of 8Synthflow4%#4 of 8Synthflow19%#1 of 12Retell AI13%#3 of 12What the models said about Retell AI
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Not recommended if you need a no-code launch or a predictable flat monthly bill.” Mistral Small · negative prompt · hard negative
“Cautious on data privacy if integrating deeply with CRMs/APIs (extra attack surfaces). Hallucinations remain a core issue.” Grok 4.20 · negative prompt · soft negative
“strong overall reviews, but users mention higher cost per call, missing features, and setup complexity in some cases” GPT-5.4 mini · negative prompt · soft negative
“Excellent for production-scale support automation; reliable for regulated industries; good balance of ease and power.” Grok 4.20 · comparative prompt · first choice
“Choose Retell AI if you want to build complex, multi-step workflows ... Their visual editor is superior here.” GLM 4.7 FlashX · comparative prompt · first choice
“Currently a market leader in this space... Choose Retell AI or Vapi if you are building a product feature” Qwen 3.7 Flash · comparative prompt · first choice
What the models said about Synthflow
Every negative label with a quote, up to three, then the highest-weighted positives, up to three. Six of eight in this category shown.
“Mistral Small warns that Synthflow may not scale well for call volumes exceeding 5,000 calls per month.” Llama 4 Maverick · negative prompt · hard negative
“Avoid if you're running high call volumes on a tight budget.” Mistral Small · negative prompt · hard negative
“Synthflow, Cognigy, Kore.ai etc. are better for larger enterprise governance needs and longer implementations.” Muse Glimmer 30B · direct prompt · soft negative
“For a company with a limited budget, Synthflow is likely the best overall choice” Perplexity Sonar · budget prompt · first choice
“Kore.ai and Synthflow are the best options” Mistral Small · direct prompt · first choice
“Synthflow is ideal for mid-size and enterprise contact centers that want a managed, no-code rollout.” Claude Haiku 4.5 · direct prompt · alternative
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.