Ambient vs Dictation Streaming Comparison

After you create an ambient session and seed the session context, you can stream audio on GET /ws/stream. For Dictation, create a transcription session, then stream on GET /ws/transcribe. Both endpoints use WebSocket and send audio as JSON text frames. They solve different jobs and use different message contracts.

This guide applies to: Direct HTTP and WebSocket integrations with Suki for Partner Ambient, Form filling, and Dictation APIs.

Endpoint	Purpose	API reference
`GET` /ws/stream	Stream PCM audio into an ambient or Form filling session for note generation and related processing	Audio streaming for Ambient and Form filling sessions
`GET` /ws/transcribe	Stream PCM_S16LE audio into a Dictation (transcription) session for real-time text	Stream audio to Dictation session

Use the same base host for REST and WebSocket in a given environment (for example staging https://sdp.suki-stage.com and wss://sdp.suki-stage.com). Your partnership team confirms which host and credentials apply.

Ambient Streaming

Stream PCM audio into an ambient session for note generation and related processing. Use this when you already have an ambient session and want to push live audio for that session.

Dictation Streaming

Stream PCM_S16LE audio into a Dictation session for real-time text. Use this when you have a Dictation session and want to push audio for that session.

Do not send raw audio as binary WebSocket frames on /ws/stream. On /ws/transcribe, outbound audio is also sent as JSON text frames with Base64 payloads, not raw binary PCM frames.

What each product is for

	Ambient (and Form filling on the same socket)	Dictation
Goal	Stream visit audio for note generation and related processing	Stream speech for real-time transcript text in your app
Endpoint	`GET /ws/stream`	`GET /ws/transcribe`
Session ID	`ambient_session_id`	`transcription_session_id`
Results	Final note and transcript mainly via REST after you end the session	Partial and final transcript frames on the WebSocket, then REST as needed

Side-by-side comparison

Topic	Ambient Streaming	Dictation Streaming
Endpoint	`GET /ws/stream`	`GET /ws/transcribe`
Browser `Sec-WebSocket-Protocol`	`SukiAmbientAuth,<sdp_suki_token>,<ambient_session_id>`	`SukiAmbientAuth,<sdp_suki_token>,<transcription_session_id>`
Non-browser headers	`sdp_suki_token`, `ambient_session_id`	`sdp_suki_token`, `transcription_session_id`
Audio field name	`data` (Base64 PCM)	`audioData` (Base64 PCM_S16LE)
Start-of-stream	`START_TIME` required first	No `START_TIME` in the Dictation contract documented here
End-of-stream	`AUDIO` with `data`: `RU9G` (Base64 of bytes `EOF`)	`EVENT` with `event`: `AUDIO_END`
Control messages	`type`: `EVENT`, `event`: enum (see FAQ)	`EVENT` / `AUDIO_END` for end of audio

Next steps

Follow Stream ambient audio when you already have an ambient session and need to push live audio on /ws/stream. Follow Stream Dictation audio when you have a Dictation session and need real-time transcript frames on /ws/transcribe. Read Streaming architecture for diagrams of how REST and WebSocket fit together for each product.

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Ambient vs Dictation Streaming Comparison

Ambient Streaming

Dictation Streaming

What each product is for

Side-by-side comparison

Next steps

Ambient Streaming

Dictation Streaming

​What each product is for

​Side-by-side comparison

​Next steps

What each product is for

Side-by-side comparison

Next steps