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With your own TTS, the agent speaks with a voice from your own voice-provider account - any voice in your library, cloned voices included - and the per-minute price drops by $0.02, because Nixflex no longer pays for the speech. Supported providers: ElevenLabs and Cartesia. Each is a hand-built streaming integration - voice is the most latency-sensitive part of a call, so this list is curated rather than open.
The connection is tested before it is saved: Nixflex runs one real synthesis against your account with the exact voice ID you enter. A wrong voice ID or a dead key is refused at save with the provider’s reason - never discovered on a live call.

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How it works

1

Find your voice ID

In your provider’s console, pick a voice and copy its ID (ElevenLabs: the Voices page; Cartesia: the voice’s UUID).
2

Connect it

In Settings → Your own TTS, or via the API below: provider, voice ID, and your provider API key.
3

Your voice speaks every phone call

Applies account-wide. Your provider bills you for the characters; the Nixflex rate drops by $0.02/min on calls your voice actually served.
Phone calls only. Web calls use high-quality 48kHz audio and keep your agent’s standard voice - the telephone integrations produce 8kHz phone audio, and Nixflex never downgrades web audio.

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If your voice fails

  • The standard voice takes over instantly for the rest of the call - callers never hear silence.
  • The call’s Events tab records a PROVIDER_FALLBACK event with the reason.
  • That call bills at the standard TTS rate - the discount applies only to calls your voice actually carried.

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Setting it up via the API

Read the configuration (the key is never included):
Disconnect (calls return to the standard voice and rate from the next call):

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Stacking the discounts

Bring everything and the rate compounds: Premium features (web calls, live monitoring) add $0.01/min only on calls that actually use them - the same actual-use law as the discounts.