xAI
Grok 4.1 Fast
Grok 4.1 Fast is a reasoning model by xAI with vision, function calling, web search, structured output — designed for complex, multi-step problem solving where accuracy matters more than speed. It supports a 2M token context window with up to 2M tokens of output. Priced at $0.2 per million input tokens and $0.5 per million output tokens, it is one of the most cost-efficient options in its class. Access Grok 4.1 Fast through Inworld Router with OpenAI SDK compatibility, built-in failover, and intelligent routing across providers.
→Function CallingWeb SearchReasoningResponse SchemaVision
Step 1 — Create Router
curl --location 'https://api.inworld.ai/router/v1/routers' \
--header 'Authorization: Basic <your-api-key>' \
--header 'Content-Type: application/json' \
--data '{
"name": "compare-frontier-models",
"defaultRoute": {
"route_id": "default",
"variants": [
{
"variant": {
"variant_id": "xai/grok-4-1-fast-a",
"model_id": "xai/grok-4-1-fast"
},
"weight": 33
},
{
"variant": {
"variant_id": "xai/grok-3-b",
"model_id": "xai/grok-3"
},
"weight": 33
},
{
"variant": {
"variant_id": "xai/grok-3-beta-c",
"model_id": "xai/grok-3-beta"
},
"weight": 34
}
]
}
}'Step 2 — Chat Completion
curl --location 'https://api.inworld.ai/v1/chat/completions' \
--header 'Authorization: Basic <your-api-key>' \
--header 'Content-Type: application/json' \
--data '{
"model": "inworld/compare-frontier-models",
"messages": [{"role": "user", "content": "Hello!"}]
}'Grok 4.1 Fast pricing and providers
Access Grok 4.1 Fast through xAI via Inworld Router or Realtime API.
| Capabilities | Input modalities | Output modalities | |||||
|---|---|---|---|---|---|---|---|
| xAI | 2M | 2M | $0.20 | $0.50 | +2 |
Other xAI models available through Inworld
Compare Grok 4.1 Fast with other xAI models available through Inworld Router or Realtime API.
Start building with Grok 4.1 Fast
Access Grok 4.1 Fast and every other model through Inworld Router or Realtime API. Create your free account and start routing in minutes.