diff --git a/fern/customization/custom-voices/cartesia.mdx b/fern/customization/custom-voices/cartesia.mdx
new file mode 100644
index 000000000..369df8498
--- /dev/null
+++ b/fern/customization/custom-voices/cartesia.mdx
@@ -0,0 +1,27 @@
+---
+title: Cartesia
+subtitle: Set up a custom Cartesia voice in Vapi
+description: Use a custom Cartesia voice in Vapi by connecting your Cartesia API key and selecting your voice.
+slug: customization/custom-voices/cartesia
+---
+
+This guide shows you how to use a voice you created with Cartesia in your Vapi assistant. Cartesia's prebuilt voices are already available in the [Voice Library](/providers/voice/overview); follow this page only to use your own custom voice.
+
+A Cartesia account and API key are required for this process.
+
+
+
+ Sign up at [Cartesia](https://play.cartesia.ai), then create a custom voice in the [Cartesia playground](https://play.cartesia.ai/voices).
+
+
+ Get your API key from your Cartesia account.
+
+
+ In the [Vapi Dashboard](https://dashboard.vapi.ai), open **Settings**, then **Integrations**, and add your Cartesia API key under **Cartesia**.
+
+ Once you save, your Cartesia voices sync automatically.
+
+
+ Open an assistant and open **Voice Settings**. Choose **Cartesia** as the provider and select your voice, or switch to **Custom Voice ID** and paste your Cartesia voice ID. You can find your voice ID in the [Voice Library](/providers/voice/overview).
+
+
diff --git a/fern/docs.yml b/fern/docs.yml
index 410c59633..88f9e041d 100644
--- a/fern/docs.yml
+++ b/fern/docs.yml
@@ -246,6 +246,8 @@ navigation:
path: customization/custom-voices/elevenlabs.mdx
- page: PlayHT
path: customization/custom-voices/playht.mdx
+ - page: Cartesia
+ path: customization/custom-voices/cartesia.mdx
- page: Custom transcriber
path: customization/custom-transcriber.mdx
icon: fa-light fa-microphone
@@ -599,6 +601,7 @@ navigation:
icon: fa-light fa-link
contents:
- section: Voices (Text-to-speech)
+ path: providers/voice/overview.mdx
icon: fa-light fa-waveform-lines
contents:
- section: Vapi Voices
diff --git a/fern/providers/voice/overview.mdx b/fern/providers/voice/overview.mdx
new file mode 100644
index 000000000..effd0504f
--- /dev/null
+++ b/fern/providers/voice/overview.mdx
@@ -0,0 +1,67 @@
+---
+title: Voices (Text-to-speech)
+subtitle: Find, preview, and use voices from any supported provider
+description: Find, preview, and use text-to-speech voices from any Vapi-supported provider, and look up a voiceId in the Vapi dashboard.
+slug: providers/voice/overview
+---
+
+Vapi supports text-to-speech (TTS) voices from many providers. You choose a voice
+by setting the `provider` and `voiceId` on your assistant's `voice` configuration.
+See [Create Assistant](/api-reference/assistants/create) in the API reference.
+
+```bash title="Set an assistant's voice"
+curl -X PATCH "https://api.vapi.ai/assistant/ASSISTANT_ID" \
+ -H "Authorization: Bearer $VAPI_API_KEY" \
+ -H "Content-Type: application/json" \
+ -d '{
+ "voice": {
+ "provider": "PROVIDER",
+ "voiceId": "VOICE_ID"
+ }
+ }'
+```
+
+This page shows you how to find a `voiceId` in the dashboard, and links to every
+supported provider.
+
+## Find a voice in the dashboard
+
+The **Voice Library** in the [Vapi Dashboard](https://dashboard.vapi.ai) lists every
+voice available to your organization. Browse and preview voices there, then copy a
+voice's ID to use on an assistant.
+
+
+
+ In the [Vapi Dashboard](https://dashboard.vapi.ai), open **Resources**, then
+ **Voice Library**. Filter by **Provider** and search by name. Press play on a
+ voice to preview it.
+
+
+ Click the copy icon on a voice to copy its ID.
+
+
+ Open an assistant and click the edit (pencil) icon on the **Voice** card to
+ open **Voice Settings**. Choose the **Provider** and **Voice**, or paste the
+ copied ID under **Custom Voice ID**.
+
+
+
+
+ Some providers also let you use your own custom voice. See [Custom voices](/customization/custom-voices/custom-voice) for setup.
+
+
+## Supported voice providers
+
+
+
+
+
+
+
+
+
+
+
+
+
+