TTS caching

Speech synthesis is often the most expensive step in a voice agent. Greetings, confirmations, and hold messages repeat on every call. TTS caching stores the audio for a phrase the first time it is synthesized, then reuses it on later calls. By policy, the cache is isolated per organisation and PII-aware, so your audio is not stored where another customer can reach it. Cached audio expires on a sliding schedule: phrases that keep coming up stay cached, and unused ones age out.

Turn it on

TTS Caching can be activated for any use case. It runs the same way whether the audio comes from an SLNG-hosted model or BYOK.

You can activate or deactivate the SLNG TTS Caching with one header.

import WebSocket from "ws";

const ws = new WebSocket(
  "wss://api.slng.ai/v1/tts/slng/deepgram/aura:2-en",
  {
    headers: {
      "X-Slng-Cache-Bypass": "false",
    },
  }
);

ws.on("open", () => {
  ws.send(JSON.stringify({ type: "text", text: "Hello from sunny Barcelona!" }));
});

ws.on("message", (data) => {
  playAudio(data); // play each chunk as it arrives
});

// Call ws.close() when the turn or session ends so the server releases resources.

The X-Slng-Cache-Bypass header works this way:False: Caching is ActivatedTrue: Caching is Disabled

SLNG models and your own keys

Caching works the same whether the agent uses an SLNG-hosted model or a model on your own provider key. There is nothing extra to set up for either.

Regions

TTS caching is region aware and organization scoped, your Speech is never synthesised or hosted in another region.

Get started

Regions

Execution layer

Agent Builder

Models

Integrate

Turn it on

SLNG models and your own keys

Regions

​Turn it on

​SLNG models and your own keys

​Regions

Turn it on

SLNG models and your own keys

Regions