Audio (Speech & Transcription)

Truememory provides OpenAI-compatible audio endpoints for speech-to-text (transcription) and text-to-speech (TTS). These are drop-in replacements for OpenAI’s /v1/audio/transcriptions and /v1/audio/speech — any client that works with OpenAI’s audio API works with Truememory by changing the base URL.

All requests require a Bearer token from Truememory Auth. Both /v1/audio/transcriptions and /v1/audio/speech accept tri-mode auth — see Ways to authenticate:

The audio endpoints are stateless (no per-user memory or thread writes), so the service-only mode is allowed for both — unlike the WebSocket voice endpoints, which require X-On-Behalf-Of because they touch user state.

Speech-to-Text (Transcription)

Convert audio to text. Truememory proxies to OpenAI Whisper and returns the transcript.

Endpoint

POST /v1/audio/transcriptions

Parameters

Send as multipart/form-data:

Example

curl -X POST https://your-tie-host/v1/audio/transcriptions \
  -H "Authorization: Bearer $TOKEN" \
  -F file=@recording.webm \
  -F model=whisper-1

Response

Default (json format):

{
  "text": "Hello, I'd like to log my breakfast. I had oatmeal with blueberries."
}

With response_format=verbose_json, the response includes timestamps and segment-level detail.

AI SDK Integration

The Vercel AI SDK supports transcription via experimental_transcribe. Point the OpenAI provider at your Truememory instance:

import { createOpenAI } from "@ai-sdk/openai";
import { experimental_transcribe as transcribe } from "ai";

const tie = createOpenAI({
  baseURL: "https://your-tie-host/v1",
  apiKey: "$TOKEN",
});

const result = await transcribe({
  model: tie.transcription("whisper-1"),
  audio: audioBuffer, // Uint8Array, Buffer, base64 string, or URL
});

console.log(result.text);
// "Hello, I'd like to log my breakfast."

Text-to-Speech

Convert text to spoken audio. Truememory proxies to OpenAI’s TTS models and streams audio bytes back.

Endpoint

POST /v1/audio/speech

Parameters

Send as JSON:

Example

curl -X POST https://your-tie-host/v1/audio/speech \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{
    "model": "gpt-4o-mini-tts",
    "input": "Great job logging your meals today! You hit your protein target.",
    "voice": "nova"
  }' \
  --output response.mp3

Response

Raw audio bytes in the requested format. The Content-Type header reflects the format (e.g. audio/mpeg for mp3).

AI SDK Integration

import { createOpenAI } from "@ai-sdk/openai";
import { experimental_generateSpeech as generateSpeech } from "ai";

const tie = createOpenAI({
  baseURL: "https://your-tie-host/v1",
  apiKey: "$TOKEN",
});

const result = await generateSpeech({
  model: tie.speech("gpt-4o-mini-tts"),
  text: "Great job logging your meals today!",
  voice: "nova",
});

// result.audio is a Uint8Array of audio bytes

Gemini TTS (same endpoint, different model)

/v1/audio/speech routes to Gemini when model is a Gemini TTS variant — same pattern as /v1/audio/transcriptions switching between Whisper and Gemini. No second endpoint to learn. For real-time conversational voice, see Real-Time Voice.

Note: Google’s OpenAI compatibility layer does not expose a TTS endpoint — only audio understanding (input). The Gemini path on /v1/audio/speech is Truememory’s own OpenAI-shaped facade that calls Gemini’s native SDK (google-genai with response_modalities=["AUDIO"]). Callers see a unified API; Truememory handles the bridging.

POST /v1/audio/speech
Authorization: Bearer <token>
Content-Type: application/json

{
  "model": "google/gemini-2.5-flash-tts",
  "input": "Great job today!",
  "voice": "Kore",
  "language": "en",
  "response_format": "pcm"
}

Differences vs OpenAI TTS

Example

# Raw PCM — 24 kHz signed 16-bit little-endian mono
curl -X POST https://your-tie-host/v1/audio/speech \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{
    "model": "google/gemini-2.5-flash-tts",
    "input": "Great job today!",
    "voice": "Kore"
  }' \
  --output response.pcm

# WAV — playable by any audio player without client-side transcoding
curl -X POST https://your-tie-host/v1/audio/speech \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $TOKEN" \
  -d '{
    "model": "google/gemini-2.5-flash-tts",
    "input": "Great job today!",
    "voice": "Kore",
    "response_format": "wav"
  }' \
  --output response.wav

Response

pcm (default): raw PCM — 24 kHz, signed 16-bit little-endian, mono. Content-Type: audio/pcm;rate=24000.

wav: same PCM wrapped in a standard 44-byte WAV header. Content-Type: audio/wav. Playable directly in browsers and mobile apps without transcoding.

Usage headers

Every successful Gemini TTS response includes token-usage headers so callers can record billing data without inspecting the audio body:

Headers are always present — they default to "0" when the SDK omits usage_metadata. The OpenAI TTS path (gpt-4o-mini-tts etc.) does not emit these headers.

Common Pattern: Voice Chat

A typical voice-enabled chat flow combines both endpoints:

1. User speaks → record audio on the client
2. Transcribe → POST /v1/audio/transcriptions → get text
3. Chat → POST /v1/chat/completions with the transcribed text → get AI response
4. Speak → POST /v1/audio/speech with the AI response text → play audio

sequenceDiagram
    participant User
    participant Client
    participant Truememory

    User->>Client: Speaks
    Client->>Truememory: POST /v1/audio/transcriptions (audio file)
    Truememory-->>Client: { "text": "..." }
    Client->>Truememory: POST /v1/chat/completions (transcribed text)
    Truememory-->>Client: AI response text
    Client->>Truememory: POST /v1/audio/speech (response text)
    Truememory-->>Client: Audio bytes
    Client->>User: Plays audio

Steps 3 and 4 can overlap — start TTS as soon as the chat response text is available, rather than waiting for the full response.

Models

Transcription

Text-to-Speech

OpenAI Voices

Gemini Voices

Used with POST /v1/audio/speech (when model=google/gemini-2.5-flash-tts) and the real-time voice agent.

Full catalog: Gemini voice options