Text Generation Model

Grok 3 Fast

Grok 3 Fast is a text generation model from X.ai designed for speed, with a 131,072 token context window.

Start Building with Grok 3 Fast View All Models

Publisher

X.ai

TypeText

Context Window131,072 tokens

ReleasedApril 2025

Input$5.00/MTok

Output$25.00/MTok

Try Grok 3 Fast →

About Grok 3 Fast

Fast text generation from X.ai's Grok 3

Grok 3 Fast is a large language model developed by X.ai, released in April 2025 as part of the Grok 3 model family. It operates under the identifier grok-3-fast-beta and is designed specifically for lower-latency text generation compared to the standard Grok 3 variant. The model supports a context window of 131,072 tokens and produces responses up to 8,192 tokens in length.

Grok 3 Fast is suited for applications where response speed is a priority, such as real-time conversational interfaces, high-throughput pipelines, and latency-sensitive workflows. It handles general-purpose text generation tasks including summarization, question answering, drafting, and instruction following. Developers accessing it through MindStudio can use it without managing API keys directly.

Capabilities

What Grok 3 Fast supports

Large Context Window

Processes up to 131,072 tokens of input in a single request, enabling long documents, extended conversations, or large codebases to be handled in one pass.

Fast Text Generation

Optimized for lower latency than the standard Grok 3 model, making it suitable for real-time and high-throughput text generation use cases.

Instruction Following

Responds to structured prompts and multi-step instructions, supporting tasks like summarization, drafting, and question answering.

Long-Form Output

Generates responses up to 8,192 tokens, allowing detailed answers, reports, or extended content in a single completion.

Chat Interface

Built as a chat-format model (llm_chat), supporting multi-turn conversation structures with system, user, and assistant message roles.

Ready to build with Grok 3 Fast?

Get Started Free

Performance

Benchmark scores

Scores represent accuracy — the percentage of questions answered correctly on each test.

Benchmark	What it tests	Score
MMLU-Pro	Expert knowledge across 14 academic disciplines	79.9%
GPQA Diamond	PhD-level science questions (biology, physics, chemistry)	69.3%
MATH-500	Undergraduate and competition-level math problems	87.0%
AIME 2024	American math olympiad problems	33.0%
LiveCodeBench	Real-world coding tasks from recent competitions	42.5%
HLE	Questions that challenge frontier models across many domains	5.1%
SciCode	Scientific research coding and numerical methods	36.8%

FAQ

Common questions about Grok 3 Fast

What is the context window size for Grok 3 Fast?

Grok 3 Fast supports a context window of 131,072 tokens, allowing large volumes of text to be processed in a single request.

What is the maximum response length?

The model can generate responses up to 8,192 tokens per completion.

How does Grok 3 Fast differ from standard Grok 3?

Grok 3 Fast is optimized for lower latency and faster response times compared to the standard Grok 3 model, making it better suited for speed-sensitive applications.

Who publishes Grok 3 Fast?

Grok 3 Fast is published by X.ai and was released in April 2025 under the model identifier grok-3-fast-beta.

What is the knowledge cutoff date for Grok 3 Fast?

The metadata provided does not specify a knowledge cutoff date. For the most accurate information, consult X.ai's official documentation.

Is pricing information available for Grok 3 Fast?

No pricing information is included in the available metadata. Check X.ai's official website or MindStudio's pricing page for current details.

Resources