Sesame CSM-1B (Conversational Speech Model)
Model idsesame/csm-1b
PricePrice not published
Checked29 September 2026
Where it stands
100newer speech and audio models since its release
- NVIDIA Nemotron 3.5 Transcribe (30B-A4B)28 Oct 2026
- Hy-SimulMT-30B-A3B22 Oct 2026
- Eleven Realtime v1 Max / Mini20 Oct 2026
- Voxtral Mini Transcribe 3 (+ Mini Transcribe Realtime 3)20 Oct 2026
- Voxtral Small Transcribe 320 Oct 2026
The 5 newest are listed. All speech and audio models
- Weights
- Weights are public under a permissive licence (Apache-2.0).
How to call it
3 ways to use Sesame CSM-1B (Conversational Speech Model), with the model id each provider expects.
| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Hugging Face | sesame/csm-1b |
huggingface.co | |
| Transformers | sesame/csm-1b |
huggingface.co | |
| Sesame app (Maya, Miles, Simone, Charlie — hosted larger models) | sesame.com |
Pricing
Price not published.
No price source linked. Checked 29 September 2026.
Specs
- Input
- Text and audio
- Output
- Audio
- Context window
- Not published
- Max output
- Not published
- Open weights
- Yes
- Licence
- Apache-2.0
- Released
- 13 March 2025
- Status
- Current
- Type
- Speech and audio
What stands out
What its maker marketed at launch, and what people found later, each with its source.
Context-conditioned conversational TTS
Llama backbone + audio decoder emitting Mimi audio codes; generates speech conditioned on prior conversation audio/text so prosody fits the dialogue; voice prompting via context segments.
Notes
Open base generation model only (no fine-tuned voices, English-centric, cannot generate text itself); the Maya/Miles demo voices use Sesame’s larger in-house models. Native in Transformers since v4.52.1. Sesame raised a $250M Series B (Oct 2025, Sequoia/Spark) and launched a public-preview iOS app with four agents (Maya, Miles, Simone, Charlie) in 39 countries on 2026-05-28; smart glasses targeted for 2027. No newer open Sesame model found as of 2026-09-29.
Sources: https://huggingface.co/sesame/csm-1b , https://techcrunch.com/2026/05/28/sesame-the-conversational-ai-startup-from-oculus-founders-launches-its-ios-app/