Grok 4 Fast is xAI's language model with a 131K context window and up to 30K output tokens, available from 3 providers, starting at $0.200 / 1M input and $0.500 / 1M output. A cost-efficient multimodal LLM from xAI with a 2M token context window, available in both reasoning and non-reasoning flavors.
Specifications
Canonical IDxai-grok-4-fast
TypeLanguage
StatusDeprecated
CreatorxAIxAI
Providers
Context Window131K tokens
Max Output30K tokens
Input ModalitiesImageText
Output ModalitiesText
Reasoning Effortsdefault
Release Date · 8 months ago
Knowledge Cutoff
Deprecation Date
Benchmarks
Intelligence Index
23.1
#198
Coding Index
19.0
#187
Math Index
41.3
#148
MMLU-Pro
0.7
#182
GPQA
0.6
#251
HLE
0.1
#285
LiveCodeBench
0.4
#169
IFBench
0.4
#252
Time to First Token
0.00s
#202
SciCode
0.3
#200
AIME 2025
0.4
#148
LCR
0.2
#249
TerminalBench Hard
0.1
#181
TAU2
0.6
#144
Output TPS
0.0
#476

Capabilities

Input2/5
Text
Image
Audio·
Video·
PDF·
Output1/5
Text
Image·
Audio·
Video·
Embedding·
Capabilities4/13
Reasoning
Adaptive Reasoning·
Function Calling
Parallel Function Calling·
Structured Outputs
Native JSON Schema
Web Search·
URL Context·
Computer Use·
Code Execution·
File Search·
Prompt Caching·
Assistant Prefill·

Pricing by Provider

ProviderStandardBatch
Input
$ / 1M
Output
$ / 1M
Cache Read
$ / 1M
Input
$ / 1M
Output
$ / 1M
Cache Read
$ / 1M
Azure AI Foundry logo
Azure AI Foundry
xai:grok4fast
$0.200$0.500N/A
xAI logo
xAI
grok-4-fast
$1.25$2.50$0.200$0.625$1.25$0.100
Oracle Cloud (OCI) logo
Oracle Cloud (OCI)
oci/xai.grok-4-fast
$5.00$25.00N/A
View Azure AI Foundry

Cost Calculator

Preset:

Versions

VersionReleasedContextInput / 1MOutput / 1MStatus
Grok 4.31.0M$1.25$2.50Available
Grok 4.202.0M$1.25$2.50Available
Grok 4.20 Multi-Agent2.0M$1.25$2.50Available
Grok 4.20 Multi-Agent Beta2.0M$1.25$2.50Available
Grok 4.20 Non-Reasoning2.0M$1.25$2.50Available
Grok 4.20 Reasoning2.0M$1.25$2.50Available
Grok 4.1 Fast2.0M$1.25$2.50Deprecated
Grok 4 Fast131K$0.200$0.500Current
Grok 4 Fast Non-Reasoning2.0M$0.200$0.500Available
Grok 4256K$1.25$2.50Deprecated
Grok 4.1 Reasoning2.0M$0.200$0.500Available

Model IDs