Voice agents Ultravox

Ultravox

Ultravox is a voice orchestration platform that connects multiple text-to-speech providers through a unified interface. Using Custom Voices, Ultravox can call external TTS APIs such as Faseeh and use those voices seamlessly inside Ultravox workflows. All you need is an active Faseeh (Munsit) account and an active Ultravox account.

1

Get your key and voice ID

Two things to collect from the Faseeh side before you touch Ultravox:

StepWhat to do
1 · Create an API keyLog in to your Faseeh account and navigate to the API / Developer section. Create a new API key and copy it — it will be used inside Ultravox.
2 · Copy the Voice IDGo to the Voices section, select the voice you want, and use the button that copies the Voice ID. Save it for later.
Keep the API key secure. It goes into your Ultravox custom-voice configuration, so treat that configuration as a secret too.
2

Add a Custom Voice in Ultravox

In the Ultravox dashboard: open Voices from the navigation, click Custom Voice, then Add Custom Voice. Fill in the two identity fields:

FieldBest practice
Voice NameUse the same name as the voice in Faseeh — it makes the voice easier to identify and manage later.
DescriptionA short description: language, dialect, gender, or intended use case.
3

Configure the Custom Voice request

Copy the configuration below into Ultravox. Replace the redacted API key with your Faseeh key, and YOUR_ar-najdi-male-2 with the Voice ID you copied.

Ultravox custom voice config
{ "url": "https://api.munsit.com/api/v1/text-to-speech/faseeh-v1-preview", "headers": { "x-api-key": "REDACTED", "Content-Type": "application/json" }, "body": { "text": "{text}", "stability": 0.5, "speed": 1.0, "streaming": true, "voice_id": "YOUR_ar-najdi-male-2" }, "responseSampleRate": 24000 }
4

Request details

Authentication: Munsit requires API key authentication using the x-api-key header. Path parameter: model_id (string, required) — the model identifier used for text-to-speech generation. The body fields:

FieldTypeRequiredDescription
voice_idstringrequiredThe Munsit voice ID used for synthesis.
textstringrequiredThe Arabic text to convert into speech — Ultravox substitutes it via the {text} placeholder.
stabilitynumberrequiredA value between 0.0 and 1.0. Higher values produce more consistent output.
speednumberoptionalA value between 0.7 and 1.2. Default is 1.0.
streamingbooleanrequiredMust be false to receive a complete WAV file response.
Prefer watching it done? There's a step-by-step video walkthrough of this setup on YouTube.
5

Where next

The Ultravox custom voice is a thin wrapper over the standard synthesis endpoint — everything about it applies here.

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