xAI
Grok 4 Fast Reasoning
Grok 4 Fast Reasoning is a xAI model with function calling and web search capabilities. It is priced at $0.2 per million input tokens and $0.5 per million output tokens, and has a 2M token context window. Access the Grok 4 Fast Reasoning API through Inworld Router or Realtime API.
→Function CallingWeb Search
curl --location 'https://api.inworld.ai/router/v1/routers' \
--header 'Content-Type: application/json' \
--header 'Authorization: Basic <your-api-key>' \
--data '{
"name": "compare-frontier-models",
"default_route": {
"route_id": "default",
"variants": [
{
"variant": { "variant_id": "xai",
"model_id": "xai/grok-4-fast-reasoning" },
"weight": 33
},
{
"variant": {
"variant_id": "xai",
"model_id": "xai/grok-3"
},
"weight": 33
},
{
"variant": {
"variant_id": "xai",
"model_id": "xai/grok-3-beta"
},
"weight": 34
}
]
}
}'Inference providers
Access Grok 4 Fast Reasoning through xAI via Inworld Router or Realtime API.
| Capabilities | Input modalities | Output modalities | |||||
|---|---|---|---|---|---|---|---|
| xAI | 2M | 2M | $0.20 | $0.50 |
More models by xAI
Other xAI models available through Inworld Router or Realtime API.
| Capabilities | Input modalities | Output modalities | Inference provider | |||||
|---|---|---|---|---|---|---|---|---|
| Grok 3 | 131.1K | 131.1K | $3.00 | $15.00 | ||||
| Grok 3 Beta | 131.1K | 131.1K | $3.00 | $15.00 | ||||
| Grok 3 Fast | — | — | $3.00 | $15.00 | — | |||
| Grok 3 Fast Beta | 131.1K | 131.1K | $3.00 | $15.00 | ||||
| Grok 3 Fast Latest | 131.1K | 131.1K | $3.00 | $15.00 | ||||
| Grok 3 Latest | 131.1K | 131.1K | $3.00 | $15.00 | ||||
| Grok 3 Mini Fast | 131.1K | 131.1K | $0.30 | $0.50 | ||||
| Grok 3 Mini Fast Beta | 131.1K | 131.1K | $0.30 | $0.50 | ||||
| Grok 3 Mini Fast Latest | 131.1K | 131.1K | $0.30 | $0.50 | ||||
| Grok 3 Mini Latest | 131.1K | 131.1K | $0.30 | $0.50 | ||||
| Grok 4 | 256K | 256K | $3.00 | $15.00 | ||||
| Grok 4 0709 | 256K | 256K | $3.00 | $15.00 | ||||
| Grok 4 Fast | — | — | $0.20 | $0.50 | — | |||
| Grok 4 Fast Non Reasoning | 2M | 2M | $0.20 | $0.50 | ||||
| Grok 4 Fast Non Reasoning Latest | — | — | $0.20 | $0.50 | — | |||
| Grok 4 Fast Reasoning Latest | — | — | $0.20 | $0.50 | — | |||
| Grok 4 Latest | 256K | 256K | $3.00 | $15.00 | ||||
| Grok 4.1 Fast | 2M | 2M | $0.20 | $0.50 | +2 | |||
| Grok 4.1 Fast Non Reasoning | 2M | 2M | $0.20 | $0.50 | +1 | |||
| Grok 4.1 Fast Non Reasoning Latest | 2M | 2M | $0.20 | $0.50 | +1 | |||
| Grok 4.1 Fast Reasoning | 2M | 2M | $0.20 | $0.50 | +2 | |||
| Grok 4.1 Fast Reasoning Latest | 2M | 2M | $0.20 | $0.50 | +2 | |||
| Grok Code Fast | 256K | 256K | $0.20 | $1.50 | ||||
| Grok Code Fast 1 | 256K | 256K | $0.20 | $1.50 | ||||
| Grok Code Fast 1 0825 | 256K | 256K | $0.20 | $1.50 |
Start building with Grok 4 Fast Reasoning
Access Grok 4 Fast Reasoning and every other model through Inworld Router or Realtime API. Create your free account and start routing in minutes.