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Fastest voice AI: how quickly each voice agent replies
Each voice AI platform's own published speed, side by side. Komms starts its reply a median of 77 ms after the caller's words arrive, measured on live phone calls.
Published figures, side by side
Voice AI platforms that answer and place real calls, each in its own words (October 2026).
| Platform | Published figure |
|---|---|
| Komms | 77 ms median Reply start, live calls Call to test: +1 (618) 228-1183 (live SSDI intake line; calls are recorded) |
| Bland AI | under 200 ms End to end |
| Telnyx | under 200 ms Not stated |
| PolyAI | under 300 ms Voice to voice |
| Twilio | 491 ms median Not stated |
| Vapi | under 500 ms Average, not stated |
| Synthflow | under 500 ms Not stated |
| Retell AI | about 600 ms Not stated |
Each vendor starts and stops its clock in a different place. What is time to first word? · Full method
Pricing compared: Retell AI pricing · Bland AI pricing · Vapi pricing · PolyAI pricing
Which voice agents you can call to test
A published number is the quickest way to hear a voice agent's speed for yourself. Checked on each vendor's own site, October 27, 2026.
| Platform | How you can try it |
|---|---|
| Komms | Call a live line: +1 (618) 228-1183 (live SSDI intake line; calls are recorded) |
| Vapi | Call a live line: +1 (844) 439-8274 |
| Retell AI | Enter your number and the agent calls you |
| Bland AI, Telnyx | Talk in the browser |
| PolyAI, Twilio, Synthflow | Sign up or book a sales demo |
What makes a voice agent slow
Every reply passes through four steps. Each one adds to the pause the caller hears.
- 1. Knowing the caller is done
- The agent waits for a short silence before it treats the caller's turn as finished. Wait too long and every reply feels late; too short and it cuts people off.
- 2. Deciding what to say
- The AI works out the answer. This is the part Komms times at 77 ms: simple turns are answered straight away, and only harder ones go to a larger AI model.
- 3. Making the voice
- The text-to-speech voice turns the first words into sound. Voice makers publish figures from under 100 ms to about 200 ms for this step.
- 4. The phone line
- The sound travels over the phone network or the internet to the caller.
What counts as fast
People leave very little silence between turns. A 2009 study of conversations in ten languages found speakers in every one avoid both talking over each other and long silences, and the average gap differed between languages by only about a quarter of a second.
On the phone, a pause of a second or more starts to feel slow. Callers say "hello?" or start talking again, and the agent and caller talk over each other. That is why the agent's own share of the pause should be as small as possible: it is the part a platform can control.
How to test it yourself
- Call from a normal phone
- Record the call on your phone or a second device.
- Ask the same things
- Use the same questions on every agent, for at least 20 turns.
- Measure the gap
- On the recording, time the silence from the end of your words to the start of the reply.
- Check the slow end
- Compare the middle turn and the slowest few. If the agent says "let me check" first, time the real answer too.
Try Komms
- $0.08 a minute, phone call included
- $15/mo per phone number
Start free — 625 minutes Call it now: +1 (618) 228-1183
The Komms number is a live Social Security disability (SSDI) intake line. It asks real screening questions and calls are recorded. Hang up any time.
Questions
- What is the fastest voice AI?
- No independent test has timed every call-taking voice AI platform the same way, so there is no proven fastest. Vendors publish their own figures on their own clocks. Bland AI and Telnyx publish under 200 ms, PolyAI under 300 ms, Vapi and Synthflow under 500 ms, Twilio ConversationRelay a 491 ms median and Retell about 600 ms. Komms publishes a 77 ms median from its live call logs, timed from the caller's words arriving as text to the reply going to the voice.
- Which voice AI has the lowest latency?
- It depends on what is timed. Among published figures for platforms that take real calls, Komms reports a 77 ms median for the agent deciding and starting its reply, measured on live calls. Bland AI and Telnyx publish under 200 ms, and Bland says its figure is end to end. Because the clocks differ, call each one to compare.
- Which AI phone agents can I call to test their speed?
- As of October 27, 2026, Komms (+1 618 228 1183, a live SSDI intake line) and Vapi (+1 844 439 8274) publish numbers you can dial. Retell AI calls you back from a form, and Bland AI and Telnyx demo in the browser.
- How fast is Komms?
- On 1,364 caller turns from 138 live phone calls on October 21 and 22, 2026, Komms handed the first words of its reply to the voice a median of 77 milliseconds after the caller's words arrived as text. 90% of turns were within 123 ms and 95% within 155 ms. That covers the agent deciding and starting its reply, not speech-to-text, the voice or the phone line.
- Why do voice AI latency numbers differ so much?
- Each vendor starts and stops the clock in a different place. Some time only the AI deciding what to say, some time the whole reply from the caller stopping to the caller hearing it. A figure is only comparable with another figure that uses the same clock.
- What latency do callers actually hear?
- All four steps added together: speech-to-text noticing the caller has finished, the agent deciding, the voice making sound, and the phone line. Outside tests on real phone calls usually find whole-reply pauses of around a second or more on most platforms.
- How do I test which voice AI is fastest for me?
- Call each agent from a normal phone, record the call, and measure the gap between the end of your words and the start of its reply on the recording. Use the same questions on each, make at least 20 turns, and compare the median and the slowest turns.
- What is a good latency for a voice AI agent?
- The whole pause a caller hears should stay well under a second. The agent's own part, deciding and starting its reply, can be a few hundred milliseconds or less; Komms measures a 77 ms median on live calls.
- Do filler phrases like "let me check" count?
- They make the agent sound sooner without answering sooner. A fair test times the first real answer separately. On Komms, 13.9% of turns opened with a short phrase like that on October 21 and 22, 2026, and those turns are counted in the 77 ms median.
- Why are my voice agent's replies slow?
- Usually one of four things: it waits too long to decide the caller has finished, a large AI model answers every turn, the voice is slow to make its first sound, or the call is routed far from where the AI runs. Time each step separately to find which one.