[AIG]Cartesian new model

src/content/docs/ai-gateway/providers/cartesia.mdx

@@ -0,0 +1,52 @@
+---
+title: Cartesia
+pcx_content_type: get-started
+sidebar:
+  badge:
+    text: Beta
+---
+
+[Cartesia](https://docs.cartesia.ai/) provides advanced text-to-speech services with customizable voice models.
+
+## Endpoint
+
+```txt
+https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/cartesia
+```
+
+## URL Structure
+
+When making requests to Cartesia, replace `https://api.cartesia.ai/v1` in the URL you are currently using with `https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/cartesia`.
+
+## Prerequisites
+
+When making requests to Cartesia, ensure you have the following:
+
+- Your AI Gateway Account ID.
+- Your AI Gateway gateway name.
+- An active Cartesia API token.
+- The model ID and voice ID for the Cartesia voice model you want to use.
+
+## Example
+
+### cURL
+
+```bash title="Request"
+curl https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/cartesia/tts/bytes \
+  --header 'Content-Type: application/json' \
+  --header 'Cartesia-Version: 2024-06-10' \
+  --header 'X-API-Key: {cartesia_api_token}' \
+  --data '{
+    "transcript": "Welcome to Cloudflare - AI Gateway!",
+    "model_id": "sonic-english",
+    "voice": {
+        "mode": "id",
+        "id": "694f9389-aac1-45b6-b726-9d9369183238"
+    },
+    "output_format": {
+        "container": "wav",
+        "encoding": "pcm_f32le",
+        "sample_rate": 44100
+    }
+}
+```