ResourcesIntegrationsLarge language models

xAI

Use xAI Grok models with your Vapi voice agent.

xAI provides language models for Vapi voice agents.

You can use xAI through Vapi’s default integration, or connect your own account in Integrations.

Supported capability

CapabilityProvider value
Language modelxai

Language model

Set model.provider to xai and model.model to one of the models Vapi currently supports:

$curl -X PATCH "https://api.vapi.ai/assistant/ASSISTANT_ID" \
>  -H "Authorization: Bearer $VAPI_API_KEY" \
>  -H "Content-Type: application/json" \
>  -d '{
>    "model": {
>      "provider": "xai",
>      "model": "grok-4.3"
>    }
>  }'

For additional API configuration options, review the XaiModel fields in the Create Assistant API reference.

ModelModel ID
Grok 4.3 Non-Reasoninggrok-4.3
Grok 4.20 Reasoninggrok-4.20-0309-reasoning
Grok 4.20 Non-Reasoninggrok-4.20-0309-non-reasoning
Grok 4 Fast Reasoninggrok-4-fast-reasoning
Grok 4 Fast Non-Reasoninggrok-4-fast-non-reasoning
Grok 3grok-3
Grok 2grok-2
Grok Betagrok-beta

You can also set the common model options temperature (0 to 2) and maxTokens (50 to 10000). If omitted, Vapi uses 0.5 and 250, respectively.

xAI text-to-speech

Configure xAI for text-to-speech.

xAI speech-to-text

Configure xAI for speech-to-text.

Model providers

Compare every language model provider Vapi supports.