api
Xây dựng với các API nhận dạng giọng nói, chuyển văn bản thành giọng nói, tác nhân giọng nói và trí tuệ âm thanh của Deepgram.
npx skills add https://github.com/deepgram/skills --skill apiDeepgram API
Build with Deepgram's speech-to-text, text-to-speech, voice agent, and audio intelligence APIs.
"Flux" names two separate products. Flux STT is conversational speech-to-text on
/v2/listen(model=flux-general-en). Flux TTS is turn-based speech synthesis on/v2/speak(model=flux-{voice}-{language}). They share a name and a design philosophy — turn-aware, built for voice agents — but they are different endpoints with different models, params, and messages. When a request just says "Flux", check whether it is about transcribing audio or producing it.
Getting Started
All API requests require authentication via API key or JWT:
- API Key:
Authorization: Token <API_KEY> - JWT:
Authorization: Bearer <JWT>
Base servers:
- REST & STT/TTS WebSocket:
https://api.deepgram.com - Voice Agent WebSocket:
https://agent.deepgram.com
How Deepgram's APIs Fit Together
┌──────────────────────────────┐
│ api.deepgram.com │
└──────────────────────────────┘
│
┌───────────┬───────────┬─────┴─────┬───────────┬───────────┐
▼ ▼ ▼ ▼ ▼ ▼
/v1/listen /v2/listen /v1/speak /v2/speak /v1/read /v1/projects/*
Nova — STT Flux — STT Aura — TTS Flux — TTS Text AI Management
REST + WSS WSS only REST + WSS REST + WSS REST only REST only
┌──────────────────────────────┐
│ agent.deepgram.com │
└──────────────────────────────┘
│
▼
/v1/agent/converse
WebSocket only
audio ──▶ STT ──▶ LLM ──▶ TTS ──▶ audio
(Deepgram orchestrates the full pipeline)
Which API Should I Use?
Audio → text (transcription)?
├─ General-purpose transcription (captions, batch, call logs, live streams with custom turn logic)
│ └─ Nova models via /v1/listen
│ ├─ Pre-recorded file → REST POST https://api.deepgram.com/v1/listen?model=nova-3
│ └─ Live stream → WSS wss://api.deepgram.com/v1/listen?model=nova-3
│
└─ Conversational audio / voice-agent-style turn detection
└─ Flux STT models via /v2/listen
└─ Live stream → WSS wss://api.deepgram.com/v2/listen?model=flux-general-en
Text → audio (speech synthesis)?
├─ General-purpose TTS (broadest voice catalog, compressed/containerized audio)
│ └─ Aura models via /v1/speak
│ ├─ One-shot → REST POST https://api.deepgram.com/v1/speak?model=aura-2-thalia-en
│ └─ Low-latency stream → WSS wss://api.deepgram.com/v1/speak?model=aura-2-thalia-en
│
└─ Voice-agent TTS (turn-based lifecycle, barge-in, cross-turn consistency)
└─ Flux TTS models via /v2/speak — model is REQUIRED, and must be flux-*
├─ Pre-render a block → REST POST https://api.deepgram.com/v2/speak?model=flux-alexis-en
└─ Live conversation → WSS wss://api.deepgram.com/v2/speak?model=flux-alexis-en
Full conversational voice agent (audio in, audio out)?
└─ WSS wss://agent.deepgram.com/v1/agent/converse
Deepgram handles STT + your configured LLM + TTS internally
Analyze text for insights?
└─ REST POST /v1/read
(summaries, sentiment, topics, intents)
Speech-to-Text: Nova (/v1/listen) vs Flux STT (/v2/listen)
Both model families are actively maintained and industry-leading. They solve different problems — pick the one that matches your use case.
Nova (/v1/listen) | Flux STT (/v2/listen) | |
|---|---|---|
| Endpoint | /v1/listen | /v2/listen |
| Available models | nova-3, nova-2, nova, enhanced, base | flux-general-en |
| Best for | General transcription — captions, subtitles, call logs, batch | Conversational audio — voice agents, interactive assistants, turn-taking UIs |
| Output | Continuous transcript stream | Structured turn events + transcripts (built-in turn state machine) |
| Turn detection | Manual (utterance_end_ms, VAD events) | Built-in (EOT, eager-EOT, turn_index) |
| Transports | REST + WebSocket | WebSocket only |
| Intelligence overlays | Yes — summarize, sentiment, topics, intents, diarize, redact, etc. | No — smaller focused param set; no smart_format / diarize / punctuate |
| Mid-session reconfig | No (reconnect to change) | Yes (Configure message updates EOT thresholds + keyterms live) |
Pick Nova (/v1/listen, model=nova-3) when:
- Generating captions, subtitles, or transcripts for recorded media
- Running batch transcription over files (REST)
- You need analytics overlays (
summarize,sentiment,topics,intents,diarize,redact) - You want WebSocket streaming with your own turn-detection logic
Pick Flux STT (/v2/listen, model=flux-general-en) when:
- Building an interactive voice agent or assistant
- You want end-of-turn detection handled for you
- You need low-latency turn signals and barge-in support
- You want to update EOT thresholds or keyterms mid-session without reconnecting
Migrating from Nova 3 to Flux STT? See the official Nova 3 → Flux migration guide.
Text-to-Speech: Aura (/v1/speak) vs Flux TTS (/v2/speak)
Both TTS families are actively maintained. /v2/speak is a new endpoint, not a replacement — /v1/speak is unchanged, and there is no aliasing, redirect, or deprecation. The families do not overlap: Aura voices are served only on /v1/speak, Flux TTS voices only on /v2/speak.
Aura (/v1/speak) | Flux TTS (/v2/speak) | |
|---|---|---|
| Endpoint | /v1/speak | /v2/speak |
| Models | aura-2-* (en, es, de, nl, fr, it, ja), aura-* | flux-{voice}-{language}, e.g. flux-alexis-en — English at launch |
model param | Optional (defaults to aura-asteria-en) | Required; an aura-* string is rejected |
| Best for | Broadest voice catalog, multilingual, compressed audio, one-shot synthesis | Voice agents — streaming LLM output, barge-in, multi-turn conversations |
| Mental model | Text buffer → audio stream | Streaming-first, turn-based conversation |
| Turn lifecycle | None | SpeechStarted → audio → Flushed → SpeechMetadata per turn (server-assigned speech_id) |
| Cross-turn context | None (reconnect to reset) | Prosody persists across turns automatically — no API surface |
| Transports | REST + WebSocket | REST (batch) + WebSocket (streaming) |
| Streaming encodings | linear16, mulaw, alaw | linear16, mulaw, alaw — raw audio only |
| Batch encodings | mp3, opus, flac, aac, linear16, mulaw, alaw + container / bit_rate | Same — but batch-only; the socket rejects them |
| Interruption | Clear discards the buffer, no feedback | Interrupt → SpeechInterrupted with text_spoken / text_remaining |
| Mid-stream reconfig | No (fixed at connection) | Yes — Configure updates speed only |
speed | 0.7–1.5 — Aura-2, English and Spanish only | Seven values, 0.85–1.15 in 0.05 steps |
expressivity | Not supported | -2…2, default 0 (beta; fixed for the connection) |
Voice Agent provider.version | v1 (the default when a provider is specified) | v2 (required) |
Pick Aura (/v1/speak) when:
- You need a language other than English, or a specific Aura voice
- You want compressed or containerized output (
mp3,opus,flac,aac) from a stream - You're doing one-shot synthesis and don't need a turn lifecycle
- You're already on Aura and nothing in Flux TTS is pulling you over — v1 is unchanged
Pick Flux TTS (/v2/speak) when:
- Building a voice agent, phone assistant, or customer-service bot
- You're streaming LLM tokens to a speaker in real time and want the lowest time-to-first-audio
- The user may barge in mid-response and you need to know what they actually heard
- You want tone to carry across turns without managing state yourself
- You're pre-rendering fixed audio (IVR prompts, notifications) with a Flux TTS voice — use the batch REST transport
Migrating from Aura? See the official Migrating from Aura to Flux TTS guide and Batch vs Streaming.
API Domains
| Domain | REST | WebSocket | Reference |
|---|---|---|---|
| Listen v1 — STT, Nova models | POST /v1/listen | wss://api.deepgram.com/v1/listen | listen.md |
| Listen v2 — STT, Flux STT (conversational) | — | wss://api.deepgram.com/v2/listen | listen.md |
| Speak v1 — TTS, Aura models | POST /v1/speak | wss://api.deepgram.com/v1/speak | speak.md |
| Speak v2 — TTS, Flux TTS (turn-based) | POST /v2/speak | wss://api.deepgram.com/v2/speak | speak.md |
| Voice Agent | GET /v1/agent/settings/think/models | wss://agent.deepgram.com/v1/agent/converse | agent.md |
| Read (Intelligence) | POST /v1/read | — | read.md |
| Models | GET /v1/models | — | models.md |
| Projects | /v1/projects/* | — | projects.md |
| Auth | POST /v1/auth/grant | — | auth.md |
| Self-Hosted | /v1/projects/*/selfhosted/* | — | self-hosted.md |
Common Mistakes to Avoid
All APIs
-
Feature flags are query params — except for Voice Agent and the v2 mid-session updates. For
/v1/listen,/v2/listen,/v1/speak, and/v2/speak, initial options go on the URL. The request body carries only audio data (REST) or audio frames (WebSocket). Exceptions:/v1/agent/conversehas no URL query params at all (all config goes in theSettingsmessage);/v2/listensupports aConfiguremessage after connection to update EOT thresholds and keyterms mid-session; and/v2/speaksupports aConfiguremessage that updatesspeedonly. Also note that/v2/listenhas a much smaller param set than/v1/listen— flags likesmart_format,diarize, andpunctuateare not available. -
Rate limits are concurrent connections, not total requests. A 429 means too many simultaneous open connections, not too high a request volume. Diarization and other compute-heavy features reduce your concurrency allowance further.
STT WebSocket (/v1/listen)
-
Send KeepAlive as a text frame, not binary. The connection closes after 10 seconds of no audio. Send
{"type":"KeepAlive"}as a text (JSON) frame every 3–5 seconds during silence. Sending it as a binary frame causes transcription delays — the audio pipeline chokes — not a silent no-op. -
Never send empty byte payloads. Sending a zero-length binary frame to
/v1/listenis treated as a close — it terminates the connection. Always check that your audio packet has length before sending. -
encodingmust match the actual audio format. Ifencoding=linear16but you're sending opus, you'll get a DATA-0000 error or garbled output. Omitencodingentirely when sending containerized formats (mp3, wav, ogg) — Deepgram detects them automatically. -
Timestamps reset on reconnect. Each new WebSocket connection restarts timestamps at 00:00:00. For real-time apps, maintain a timestamp offset across reconnections or you'll silently corrupt your transcript timeline.
TTS WebSocket (/v1/speak)
-
Don't send empty text. A
Speakmessage with an emptytextfield returns a 400 error. Always validate input before sending. -
Character rate limiting (DATA-0001) means slow down, not retry. If you hit this, reduce how fast you're submitting text chunks — don't immediately retry or you'll compound the problem.
Flux TTS (/v2/speak)
-
modelis required, and must be aflux-*voice. Unlike/v1/speakthere is no default — a connection or request withoutmodelis rejected. Aura strings are rejected on/v2/speak, and Flux voices are not served by/v1/speak; the two families never mix. Model strings areflux-{voice}-{language}, e.g.flux-alexis-en. There is no version segment — generations roll forward behind a stable name, as with Flux STT. -
Flushends the turn — it is not a v1-style buffer flush. There is noFinalize; it's folded intoFlush. Audio starts streaming on its own before you flush, so don't wait to send text. Use the turn'sSpeechMetadata(notFlushed) as your end-of-turn signal — it arrives once all of the turn's audio has been sent, and carries the billing and timing counts, so you can drop client-side character or duration tracking. The server assigns the turn'sspeech_id; never send one yourself. -
Streaming is raw audio only, and rejects anything it doesn't recognize. The WebSocket emits non-containerized audio, so
encodingis limited tolinear16(default),mulaw, oralaw. The compressed and containerized encodings (mp3,opus,flac,aac) and thecontainer,bit_rate,callback,callback_method, andpriorityparams are batch-only — sending them to the socket fails the connection, as does any unknown or misspelled param. Use the batch REST transport when you need compressed output. -
Insert whitespace between separate generations — the server won't. Text normalization runs before synthesis, but successive
Speakmessages are concatenated verbatim. Sending"Hello world."then"How are you?"is processed as"Hello world.How are you?", which causes sentence-boundary artifacts. Add a single space (or the right separator for non-whitespace languages) when you stitch a reply, a tool-call result, and another reply together. Send plain text: SSML and other markup is stripped, with anINPUT_MARKUP_STRIPPEDwarning.
Voice Agent (/v1/agent/converse)
-
Send the
Settingsmessage before any audio. The agent ignores everything until it receives and acknowledges the Settings configuration. Message ordering is strictly required. -
agent.speak.provider.versionselects the TTS family — and omittingagent.speaknow gives you Flux TTS. Setversiontov2for Flux TTS orv1for Aura; when you specify a provider but omitversion, it defaults tov1. But if you omitagent.speakentirely, the agent defaults to Flux TTS with theflux-kit-envoice. Switch families by changingversionandmodeltogether — aflux-*model underv1, or anaura-*model underv2, is invalid:{ "agent": { "speak": { "provider": { "type": "deepgram", "version": "v2", "model": "flux-alexis-en" } } } }
Flux STT model (/v2/listen)
-
Use
/v2/listenandmodel=flux-general-en./v1/listendoes not support Flux STT.model=fluxalone is not a valid value. Do not includelanguageorencodingparams for containerized audio. -
Use
Configureto update EOT thresholds and keyterms mid-session. Unlike/v1/listen, Flux STT supports live reconfiguration after connection — no need to reconnect to change turn detection sensitivity or boost new keyterms:{ "type": "Configure", "thresholds": { "eot_threshold": "0.8", "eot_timeout_ms": "3000" }, "keyterms": ["Deepgram"] }The server responds with
ConfigureSuccess(echoing back applied values) orConfigureFailure. Omitted threshold fields keep their current values.
Authentication
- JWT TTL applies only to the initial handshake. Tokens default to 30 seconds. Once the WebSocket connection is established, the token expiring does not close it — tokens are only needed for the upgrade request.
SDK-Specific Skills
This api skill covers the product contracts (endpoints, query params, message shapes) that are identical across SDKs. For language-idiomatic code — imports, async patterns, builder APIs, common errors — install the SDK-specific skills. Each Deepgram SDK publishes 7 product skills named deepgram-{lang}-{product} (e.g. deepgram-python-speech-to-text, deepgram-js-voice-agent) plus a maintainer skill deepgram-{lang}-maintaining-sdk. The deepgram-{lang}- prefix avoids collisions when you install skills from multiple SDKs.
# Install all skills from a specific SDK
npx skills add deepgram/deepgram-python-sdk # Python
npx skills add deepgram/deepgram-js-sdk # JavaScript / TypeScript
npx skills add deepgram/deepgram-java-sdk # Java
npx skills add deepgram/deepgram-go-sdk # Go
npx skills add deepgram/deepgram-rust-sdk # Rust
npx skills add deepgram/deepgram-swift-sdk # Swift
npx skills add deepgram/deepgram-kotlin-sdk # Kotlin
npx skills add deepgram/deepgram-dotnet-sdk # C# / .NET
npx skills add deepgram/deepgram-browser-sdk # Browser TypeScript
# Or install a specific product skill from one SDK (note the deepgram-{lang}- prefix)
npx skills add deepgram/deepgram-python-sdk --skill deepgram-python-speech-to-text
npx skills add deepgram/deepgram-js-sdk --skill deepgram-js-voice-agent
Related Deepgram skills
| Skill | Purpose |
|---|---|
recipes | Minimal runnable snippets per feature per language |
examples | Full integration examples with third-party platforms (Twilio, LiveKit, etc.) |
starters | Runnable starter apps (framework × feature matrix) |
docs | Navigate Deepgram documentation |
setup-mcp | Install the Deepgram MCP server |