# Batch vs Streaming: Which Should I Use?

Flux TTS is served on `/v2/speak` over two transports against the same voices. They're not tiers — pick by how the audio is consumed.

## The short answer

- **Building a voice agent or any live, conversational experience?** Use **[streaming](/guides/flux-tts-quickstart)** (WebSocket) — it streams audio as text arrives and keeps prosody consistent across turns.
- **Pre-rendering audio you know up front** (IVR prompts, notifications, audiobook lines)? Use **[batch](/guides/flux-tts-batch)** (REST).

## Side by side

|                                     | Streaming (WebSocket)                                 | Batch (REST)                                                         |
| ----------------------------------- | ----------------------------------------------------- | -------------------------------------------------------------------- |
| Endpoint                            | `wss://api.deepgram.com/v2/speak`                     | `POST https://api.deepgram.com/v2/speak`                             |
| Input                               | Text streamed in as it's produced (LLM tokens)        | One complete block of text                                           |
| Output                              | Audio streams back incrementally                      | Full audio in one response                                           |
| Time-to-first-byte                  | Low — playback starts before the full response exists | Whole clip generated before you get it                               |
| Interruption / barge-in             | Yes — `Interrupt` with spoken-text feedback           | N/A                                                                  |
| Turn lifecycle & cross-turn context | Yes                                                   | N/A (stateless request/response)                                     |
| Mid-stream control                  | `Configure` speed mid-session                         | Fixed per request (`speed` query parameter)                          |
| Encodings                           | Raw `linear16` / `mulaw` / `alaw`                     | Containerized/compressed too: `mp3` (default), `opus`, `flac`, `aac` |
| Operational model                   | Long-lived connection, lifecycle to manage            | Stateless: simple retries, high fan-out                              |

## Choose streaming when

- The text is produced incrementally (you're streaming from an LLM).
- The user may barge in mid-response — `Interrupt` cancels in-flight synthesis and reports what they heard.
- You want the lowest possible time-to-first-audio in a back-and-forth conversation.
- You want tone to carry across turns.

## Choose batch when

- The full text is known before you synthesize.
- You're pre-generating reusable assets (prompts, notifications, narration).
- You want a stateless request/response with easy retries and high concurrency, and don't need incremental playback or interruption.

## Related resources

- [Real-Time / Conversational Getting Started](/guides/flux-tts-quickstart)
- [Batch (REST) Getting Started](/guides/flux-tts-batch)
- [Build a Flux TTS Voice Agent](/guides/flux-tts-voice-agent)

***

## Related pages

- [Amazon SageMaker](./amazon-sagemaker-index.md)
- [Aura](./aura-index.md)
- [Changelog](../changelog.md)
- [Custom Vocabulary](./custom-vocabulary-index.md)
- [Deepgram's Docs](../index.md)
- [Deployment](./deployment-index.md)
- [Docker/Podman](./docker-podman-index.md)
- [Features](./features-index.md)
- [Flux TTS](./flux-tts-index.md)
- [Formatting](./formatting-index.md)

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