Sesame CSM 1B
Sesame CSM 1B text to speech — conversational speech for assistants, billed on input length.
A conversational speech model whose voices split along a useful axis: conversational voices for dialogue and assistant turns, read-speech voices for narration.
No credit card required. Takes 30 seconds.
2,400+
Developers
1.2M+
API calls served
100+
Endpoints
$0.01
Per call
Yep, that's it.
Playground coming soon — use the API endpoint directly with your API key.
Pricing
Per character: $0.0148/1K chars
Endpoint
/v1/media/queue
Strengths
Voice families are split by purpose, so an assistant turn and a narration passage each get the right delivery.
Designed for back-and-forth conversation rather than long monologue.
At 1B parameters it stays affordable enough for every turn of a conversation.
Focused on doing one language well.
Quick start
Copy this snippet and start making calls with Sesame CSM 1B.
// Step 1: Submit job
const res = await fetch('https://api.yepapi.com/v1/media/queue', {
method: 'POST',
headers: {
'x-api-key': 'YOUR_API_KEY',
'Content-Type': 'application/json',
},
body: JSON.stringify({
"model": "sesame/csm-1b",
"prompt": "Sure — I can do that. Do you want me to send it now, or wait until the rest of the team has signed off?",
"options": {
"voice": "conversational_a"
}
}),
});
const { data } = await res.json();
const jobId = data.jobId;
// Step 2: Poll for result
const status = await fetch(`https://api.yepapi.com/v1/media/status/${jobId}`, {
headers: { 'x-api-key': 'YOUR_API_KEY' },
});
const { data: job } = await status.json();
// job.status: "pending" | "processing" | "completed" | "failed"
// job.result: { text?, image?, audio?, video? }Why use Sesame CSM 1B through YepAPI?
Sesame CSM 1B API — conversational speech synthesis
CSM 1B is a conversational speech model from Sesame. Its voice options split along a useful axis: `conversational_*` voices for dialogue and assistant turns, `read_speech_*` voices for narration and read-aloud content.
At 1B parameters it stays cheap enough to synthesise every turn of a live conversation. Billed at $0.0148 per 1,000 characters on YepAPI.
Start generating in 30 seconds
$5 free credit on signup. No credit card required. Pay per call.
What developers say
“Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.”
“One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.”
“The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.”
Frequently asked questions
A conversational speech model whose voices split along a useful axis: conversational voices for dialogue and assistant turns, read-speech voices for narration.
Pricing for Sesame CSM 1B through YepAPI is based on usage. No monthly minimums — you only pay for what you use.
Sign up for a free API key, then send requests to the /v1/media/queue endpoint.
Ready to use Sesame CSM 1B?
$5 free credit on signup. No credit card required. Pay per call.
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