Text-to-Speech

Generate natural-sounding speech from text

Multiple voices, streaming support, multilingual.

Endpoint

POST /voice/v1/speak

cURL

curl -X POST https://api.case.dev/voice/v1/speak \
  -H "Authorization: Bearer sk_case_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "The court finds in favor of the plaintiff.",
    "voice_id": "EXAVITQu4vr4xnSDxMaL"
  }' \
  --output ruling.mp3

Parameters

Parameter	Type	Required	Description
text	string	Yes	Text to convert to speech
voice_id	string	No	Voice ID (default: Rachel)
output_format	string	No	Audio format (default: mp3_44100_128)
language_code	string	No	Language for multilingual voices

List voices

Get available voices:

cURL

curl https://api.case.dev/voice/v1/voices \
  -H "Authorization: Bearer sk_case_YOUR_API_KEY"

Popular voices

Voice	ID	Description
Rachel	EXAVITQu4vr4xnSDxMaL	Professional, clear (default)
Adam	21m00Tcm4TlvDq8ikWAM	Deep, authoritative
Antoni	ErXwobaYiN019PkySvjV	Well-rounded, calm
Josh	TxGEqnHWrfWFTfGW9XjX	Deep, narrative

Streaming

For lower latency, stream audio as it’s generated:

Endpoint

POST /voice/v1/speak/stream

cURL

curl -X POST https://api.case.dev/voice/v1/speak \
  -H "Authorization: Bearer $CASEDEV_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{}'

Output formats

Format	Description
mp3_44100_128	MP3, 44.1kHz, 128kbps (default)
mp3_44100_192	MP3, 44.1kHz, 192kbps
pcm_16000	PCM, 16kHz
pcm_44100	PCM, 44.1kHz

Examples

Narrate a document summary

Typescript

const audio = await client.voice.v1.speak.create({
  text: `Summary of Smith v. Hospital: The plaintiff alleges medical
         malpractice during a surgical procedure on March 15, 2024...`,
  voice_id: 'EXAVITQu4vr4xnSDxMaL'
});

The casedev CLI does not yet expose a text-to-speech command — use cURL or an SDK. You can still browse the voice catalog with casedev voice:v1 list-voices.

Multilingual

Typescript

const audio = await client.voice.v1.speak.create({
  text: 'El tribunal falla a favor del demandante.',
  language_code: 'es'
});

Pricing: $0.30 per 1,000 characters. A 5,000 character document costs$1.50.