Grok 4 Fast Reasoning
xAIDec 1, 2025N/A
Open weights
The budget long-context king: weights released openly late last year with a full 2M-token window at pennies per million. Still unmatched when you need enormous documents for the least money.
- Status
- Generally available
- License
- Open weights · Custom
- Context window
- 2M
- Max output
- 32K
- Input · $/M
- $0.2
- Output · $/M
- $0.8
- Cached input · $/M
- $0.05
- Blended · $/M
- $0.35
- Parameters
- Undisclosed
- Inputs
- Text + images
Benchmarks
This model has no published scores on the benchmarks we track yet. Specs and pricing below the fold are still fully sourced.
Reasoning & knowledge
GPQA Diamond
no public score
MMLU-Pro
no public score
Humanity's Last Exam
no public score
ARC-AGI-2
no public score
Coding
SWE-bench Verified
no public score
SWE-bench Pro
no public score
LiveCodeBench
no public score
Agents & computer use
Terminal-Bench 2
no public score
OSWorld 2.0
no public score
BrowseComp
no public score
Math
AIME 2026
no public score
Known strengths
- 2M-token context
- $0.20/$0.80 pricing
- Downloadable weights
Caveats
- One generation behind current xAI flagships