Cozzo-tested · Oct 20, 2026
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Vapi vs Retell AI: tested on real phone calls
On our phone calls, Retell AI replied faster: a 1.04 s median versus 1.56 s for Vapi, a gap of 0.52 s.
Reply time is the gap from the end of the caller’s speech to the agent’s first reply audio, timed from our recording of real phone calls (Twilio calling each vendor from a US number, Ashburn, Virginia (US East)), on each vendor’s default model and voice, with the same short dental-receptionist script. Twilio added about $0.01/min for the phone leg (SIP dial-out plus recording). Small samples: differences of a few hundredths of a second are noise. Ranking order comes only from the measured medians.
Vapi
Vapi’s $0.05/min hosting plus pass-through model, transcription and voice charges.
One reply began 0.26 s before the caller audio ended.
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Retell AI
With Retell’s default voice and LLM; Retell lists $0.07–0.31/min depending on the voice and model you pick.
- Full phone-call benchmark: all 8 platforms, method and limits.
- Vapi vs Retell AI: pricing and features side by side, with a cost-at-volume calculator.
- Methodology and how we test.
Other head-to-heads
- Vapi vs ElevenLabs Agents
- Retell AI vs ElevenLabs Agents
- Vapi vs Ultravox
- Vapi vs Bland AI
- Retell AI vs Bland AI
Cozzo may earn a commission if you sign up through some links. It never affects our rankings or test results.