Skip to main content
Gradium is a bundled text-to-speech provider for OpenClaw. It can generate normal audio replies, voice-note-compatible Opus output, and 8 kHz u-law audio for telephony surfaces.

​
Setup

Create a Gradium API key, then expose it to OpenClaw: 
export GRADIUM_API_KEY="gsk_..."
You can also store the key in config under messages.tts.providers.gradium.apiKey.

​
Config

{
  messages: {
    tts: {
      auto: "always",
      provider: "gradium",
      providers: {
        gradium: {
          voiceId: "YTpq7expH9539ERJ",
          // apiKey: "${GRADIUM_API_KEY}",
          // baseUrl: "https://api.gradium.ai",
        },
      },
    },
  },
}

​
Voices

NameVoice ID
EmmaYTpq7expH9539ERJ
KentLFZvm12tW_z0xfGo
TiffanyEu9iL_CYe8N-Gkx_
Christina2H4HY2CBNyJHBCrP
SydneyjtEKaLYNn6iif5PR
JohnKWJiFWu2O9nMPYcR
Arthur3jUdJyOi9pgbxBTK
Default voice: Emma.

​
Output

  • Audio-file replies use WAV.
  • Voice-note replies use Opus and are marked voice-compatible.
  • Telephony synthesis uses ulaw_8000 at 8 kHz.