xAI model product
Grok 4 Fast Reasoning
Pushing the Frontier of Cost-Efficient Intelligence.
Updated Aug 17, 2026. Default version: Grok-4 Fast Reasoning
LLMBoard Text Score52.8Grok-4 Fast Reasoning
Coverage100%17 benchmark families
Context window2MTokens
Official input priceN/AOfficial price unavailable
Grok 4 Fast Reasoning Capability Profile
This profile uses the model's current scored version. Arena ratings and prices are shown separately.
Grok 4 Fast Reasoning Benchmark Results
Benchmark scores for Grok-4 Fast Reasoning.
No benchmark results
No benchmark result is linked to the scored version.
Grok 4 Fast Reasoning Arena Results
Preference and agent-evaluation results for the default version.
Sort by
Arena | Category | Rank | Rating / score | Votes | Observations | Result date |
|---|
| Arenawebdev | Categoryoverall | Rank114 | Rating / score1161.2 | Votes732 | ObservationsN/A | Result date |
| Arenatext factuality | Categoryoverall | Rank118 | Rating / score1415.7 | Votes10,844 | ObservationsN/A | Result date |
| Arenatext style control | Categoryoverall | Rank133 | Rating / score1403.7 | Votes18,806 | ObservationsN/A | Result date |
| Arenatext | Categoryoverall | Rank135 | Rating / score1397.7 | Votes18,806 | ObservationsN/A | Result date |
Grok 4 Fast Reasoning Pricing
Official vendor API pricing appears first, followed by individual provider offers.
- Official API
- N/A
- Official provider
- N/A
- Lowest third-party
- From $0.18 input, $0.45 output per 1M via Jiekou.AI
- Tracked offerings
- 4
Sort by
Provider | Provider model ID | Region | Input / 1M | Output / 1M | Context | Updated |
|---|
| ProviderJiekou.AI | Provider model IDgrok-4-fast-reasoning | Regionglobal | Input / 1M$0.18 | Output / 1M$0.45 | Context2M | Updated |
| ProviderHelicone | Provider model IDgrok-4-fast-reasoning | Regionglobal | Input / 1M$0.20 | Output / 1M$0.50 | Context2M | Updated |
| Provider302.AI | Provider model IDgrok-4-fast-reasoning | Regionglobal | Input / 1M$0.20 | Output / 1M$0.50 | Context2M | Updated |
| ProviderPoe | Provider model IDxai/grok-4-fast-reasoning | Regionglobal | Input / 1M$0.20 | Output / 1M$0.50 | Context2M | Updated |
Official prices use only the vendor's configured official Provider and positive standard USD PAYG rates. Third-party offers remain explicitly labeled.
Grok 4 Fast Reasoning Runtime Performance
Provider-specific output speed and catalog latency for Grok-4 Fast Reasoning. Runtime does not affect the capability score.
Sort by
Provider | Output Speed | Catalog Latency | Max Input | Max Output | Updated |
|---|
| ProviderxAI | Output Speed21.769 tok/s | Catalog Latency1.483 s | Max Input2M | Max Output30K | Updated |
Output Speed is generated output tokens received per second. Catalog latency is reported separately from observed provider TTFT.
Grok 4 Fast Reasoning Specifications
Technical details for the model's default version.
- Version
- Grok-4 Fast Reasoning
- Released
- Aug 28, 2025
- Knowledge cutoff
- Unknown
- Parameters
- N/A
- Context window
- 2M
- Max output
- 30K
- Inputs
- image, text
- Outputs
- text
- Open weights
- No
- License
- Proprietary
Grok 4 Fast Reasoning Versions
Available versions of this model. The score column identifies the version used in the overall ranking.
Sort by
Version | Released | LLMBoard | Parameters | Context | Max output | Open weights | License |
|---|
| VersionGrok-4 Fast Reasoning | Released | LLMBoard52.8 | ParametersN/A | Context2M | Max output30K | Open weightsNo | LicenseProprietary |
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What is Grok 4 Fast Reasoning?
Key information about Grok 4 Fast Reasoning and its available data.
Pushing the Frontier of Cost-Efficient Intelligence. Grok-4 Fast Reasoning is a high-speed variant of Grok-4 optimized for faster inference while maintaining strong reasoning capabilities through thinking tokens.
Data as of 2026-08-17.
FAQ
Common questions about Grok 4 Fast Reasoning.
When was Grok 4 Fast Reasoning released?
Grok 4 Fast Reasoning's default version was released on Aug 28, 2025.
How much does Grok 4 Fast Reasoning cost?
No official standard PAYG price is currently available for Grok 4 Fast Reasoning. The lowest tracked third-party offer starts at $0.18 input and $0.45 output via Jiekou.AI.
Who created Grok 4 Fast Reasoning?
Grok 4 Fast Reasoning was created by xAI.
What is the context window for Grok 4 Fast Reasoning?
The default version has a 2M token context window.
Is Grok 4 Fast Reasoning open weight?
No. The default version is not marked as having publicly available weights.
How many API providers offer Grok 4 Fast Reasoning?
4 provider offerings are linked to the default version.
What models should I compare Grok 4 Fast Reasoning with?
Nearby ranked alternatives include Grok 4.1 Fast Reasoning, MiniMax M2.1, Qwen3 VL 235B A22B Thinking.