AssemblyAI

OverviewCopy Anchor Link

pipedog ports both of Pipecat's AssemblyAI speech-to-text services:

• AssemblyAISTTService: Universal-Streaming v3 over a WebSocket, with turn detection, keyterms, diarization, language detection and hot-updatable settings.
• AssemblyAISyncSTTService: AssemblyAI's sync HTTP API for segmented (VAD-bounded) audio, with optional pre-warming and conversation context.

The same package has AssemblyAI's text-to-speech service.

InstallationCopy Anchor Link

bun add @pipedog/assemblyai

PrerequisitesCopy Anchor Link

• An AssemblyAI account and API key, passed as apiKey (the examples read ASSEMBLYAI_API_KEY).

AssemblyAISTTServiceCopy Anchor Link

ConfigurationCopy Anchor Link

SettingsCopy Anchor Link

Runtime-updatable settings, passed as settings: new AssemblyAISTTService.Settings({...}). Settings you leave out keep their defaults.

More (languageDetection, domain, voiceFocus, mode, ...) are listed on AssemblyAISTTSettings.

UsageCopy Anchor Link

import { AssemblyAISTTService } from "@pipedog/assemblyai/stt";
import { STTUpdateSettingsFrame } from "@pipedog/core/frames/frames";
import { Language } from "@pipedog/core/transcriptions/language";

const stt = new AssemblyAISTTService({
  apiKey: process.env.ASSEMBLYAI_API_KEY ?? "",
  settings: new AssemblyAISTTService.Settings({
    model: "universal-3-6-pro",
    keytermsPrompt: ["pipedog", "Pipecat"],
    languageCodes: [Language.EN, Language.ES],
  }),
});

NotesCopy Anchor Link

• Emits InterimTranscriptionFrame for partial turns and TranscriptionFrame for final turns; fires on_end_of_turn.
• With vadForceTurnEndpoint (default), a VAD stop sends ForceEndpoint.

Update settings mid-call; fields AssemblyAI supports are sent as UpdateConfiguration without reconnecting:

// Hot-updatable settings apply without reconnecting.
const update = new STTUpdateSettingsFrame({
  delta: new AssemblyAISTTService.Settings({ languageCodes: [Language.ES] }),
});

AssemblyAISyncSTTServiceCopy Anchor Link

ConfigurationCopy Anchor Link

SettingsCopy Anchor Link

Runtime-updatable settings, passed as settings: new AssemblyAISyncSTTService.Settings({...}). Settings you leave out keep their defaults.

NotesCopy Anchor Link

• Pass fetch to use your own HTTP client; warm() and enablePrewarming call /v1/warm.

RuntimesCopy Anchor Link

Generated from pipecat.runtimes and pipecat.compat in packages/assemblyai/package.json: ✅ means the compat smoke test passes on that runtime.

The service uses fetch and the global WebSocket (through core's websocketConnect, which sends the auth header on the handshake on Cloudflare Workers too). Pass no SDK; nothing is Node-only. The Sync service uses fetch only.