Model Comparison
Grok 4 Fast vs LongCat-Flash-ThinkingWhich is better in 2026?
Grok 4 Fast significantly outperforms across most benchmarks. Grok 4 Fast is 1.9x cheaper per token.
Verdict: Grok 4 Fast vs LongCat-Flash-Thinking — which is better?
Grok 4 Fast (by xAI) and LongCat-Flash-Thinking (by Meituan) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
Grok 4 Fast outperforms in 3 benchmarks (AIME 2025, GPQA, LiveCodeBench), while LongCat-Flash-Thinking is better at 0 benchmarks. Grok 4 Fast significantly outperforms across most benchmarks.
On price, Grok 4 Fast is roughly 1.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok 4 Fast also accepts a larger context window (2,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Grok 4 Fast if…
- you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
- cost matters — it's about 1.9x cheaper per token
- you process long inputs — it offers a 2,000,000 token context window
Choose LongCat-Flash-Thinking if…
- you want the most recent training data — it shipped Sep 2025
- you need open weights you can self-host or fine-tune
Performance Benchmarks
Comparative analysis across standard metrics
Grok 4 Fast outperforms in 3 benchmarks (AIME 2025, GPQA, LiveCodeBench), while LongCat-Flash-Thinking is better at 0 benchmarks.
Grok 4 Fast significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Grok 4 Fast ($0.20/1M tokens) is 1.5x cheaper than LongCat-Flash-Thinking ($0.30/1M tokens).
For output processing, Grok 4 Fast ($0.50/1M tokens) is 2.4x cheaper than LongCat-Flash-Thinking ($1.20/1M tokens).
In conclusion, LongCat-Flash-Thinking is more expensive than Grok 4 Fast.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok 4 Fast accepts 2,000,000 input tokens compared to LongCat-Flash-Thinking's 128,000 tokens. LongCat-Flash-Thinking can generate longer responses up to 128,000 tokens, while Grok 4 Fast is limited to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Grok 4 Fast supports multimodal inputs, whereas LongCat-Flash-Thinking does not.
Grok 4 Fast can handle both text and other forms of data like images, making it suitable for multimodal applications.
Grok 4 Fast
LongCat-Flash-Thinking
License
Usage and distribution terms
Grok 4 Fast is licensed under a proprietary license, while LongCat-Flash-Thinking uses MIT.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
Grok 4 Fast was released on 2025-08-28, while LongCat-Flash-Thinking was released on 2025-09-22.
LongCat-Flash-Thinking is 1 month newer than Grok 4 Fast.
Aug 28, 2025
10 months ago
Sep 22, 2025
10 months ago
3w newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Grok 4 Fast is available from xAI. LongCat-Flash-Thinking is available from Meituan.
Grok 4 Fast
LongCat-Flash-Thinking
Outputs Comparison
Key Takeaways
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Grok 4 Fast and LongCat-Flash-Thinking side-by-side, then vote on the output you prefer.
| Feature | | |
|---|
FAQ
Common questions about Grok 4 Fast vs LongCat-Flash-Thinking.