Retell
- Strength
- Leads repeatable reliability at 75.61% pass³.
- What can be improved
- The transcript captured a phone number correctly, but a different number was sent to the tool.
STT, LLM and TTS
- accurate (Retell-managed STT)
- gpt-5.5
- eleven_flash_v2
All platform comparisons
Retell · ranked 1 of 8Telnyx · ranked 4 of 8
Retell vs Telnyx
Retell is ahead on repeatable reliability, tool call accuracy, voice tone and clarity and interruption handling, and Telnyx on task completion, infrastructure reliability and response time.
Last updated Methodology by Luis Ojeda
Verdict
Which to pick
Pick Retell for reliability across repeated runs (7.32 points higher), accurate tool calls (0.13 higher), how the agent sounds (0.15 higher) and handling interruptions (0.37 higher). Pick Telnyx for completing the caller's task (3.68 points higher), calls that connect and stay up (1.63 points higher) and fast replies (0.39s faster).
Head to head
Every metric, side by side
Bars share one scale across all 8 platforms. The place next to each figure is its rank in the field.
Repeatable reliability
Share of the 82 scenarios that passed on all three runs.
- Retell
- 75.61%1st
- Telnyx
- 68.29%4th
Retell, 7.32 points higher
Task completion
Calls where the expected outcome was fully reached.
- Retell
- 93.88%5th
- Telnyx
- 97.56%1st
Telnyx, 3.68 points higher
Infrastructure-clean calls
Calls with no connection, audio or platform failure.
- Retell
- 98.37%4th
- Telnyx
- 100.00%1st
Telnyx, 1.63 points higher
Tool call accuracy
Mean score for calling the right tool with the right arguments.
- Retell
- 4.84/51st
- Telnyx
- 4.71/53rd
Retell, 0.13 higher
Voice tone and clarity
Mean score for how clear and natural the agent sounds.
- Retell
- 4.36/52nd
- Telnyx
- 4.21/55th
Retell, 0.15 higher
Interruption handling
Mean score for yielding and recovering when the caller cuts in.
- Retell
- 5.00/51st
- Telnyx
- 4.63/58th
Retell, 0.37 higher
Mean response time
Mean time for the agent to start replying after the caller stops.
- Retell
- 2.21s5th
- Telnyx
- 1.82s3rd
Telnyx, 0.39s faster
246 calls per platform: 82 scenarios, 3 runs each.
On the calls
What each platform ran, and what we saw
Telnyx
- Strength
- Tied for first in task completion at 97.56% across all 246 calls.
- What can be improved
- An opening interruption led the agent into plan discussion before completing the recording notice and TPMO disclosure.
STT, LLM and TTS
- deepgram/nova-3
- zai-org/GLM-5.2
- Telnyx Ultra
Frequently asked questions
Is Retell or Telnyx more reliable?
Retell is more reliable, by 7.32 points. Retell passed 75.61% of the 82 scenarios on all 3 runs and Telnyx passed 68.29%. A scenario only counts when every run of it passed.
Which responds faster, Retell or Telnyx?
Telnyx starts replying sooner, 0.39s faster. Mean response time is 2.21s for Retell and 1.82s for Telnyx.
Which completes more calls, Retell or Telnyx?
Retell reached the expected outcome on 93.88% of calls and Telnyx on 97.56%. Telnyx is ahead on task completion.
How were Retell and Telnyx tested?
Both ran the same Appointment and Medicare agents through the same 82 caller scenarios, 3 times each, with the same evaluators and mock tools. Only the platform and its speech and model components changed.