Model Comparison
DeepSeek-V4-Flash-0731 vs Grok 4 FastWhich is better in 2026?
Comparing DeepSeek-V4-Flash-0731 and Grok 4 Fast across benchmarks, pricing, and capabilities.
Verdict: DeepSeek-V4-Flash-0731 vs Grok 4 Fast — which is better?
DeepSeek-V4-Flash-0731 (by DeepSeek) and Grok 4 Fast (by xAI) 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.
On price, DeepSeek-V4-Flash-0731 is roughly 2.4x 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 DeepSeek-V4-Flash-0731 if…
- cost matters — it's about 2.4x cheaper per token
- you want the most recent training data — it shipped Jul 2026
- you need open weights you can self-host or fine-tune
Choose Grok 4 Fast if…
- you process long inputs — it offers a 2,000,000 token context window
Performance Benchmarks
Comparative analysis across standard metrics
DeepSeek-V4-Flash-0731 and Grok 4 Fastdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, DeepSeek-V4-Flash-0731 ($0.09/1M tokens) is 2.2x cheaper than Grok 4 Fast ($0.20/1M tokens).
For output processing, DeepSeek-V4-Flash-0731 ($0.18/1M tokens) is 2.8x cheaper than Grok 4 Fast ($0.50/1M tokens).
In conclusion, Grok 4 Fast is more expensive than DeepSeek-V4-Flash-0731.*
* 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 DeepSeek-V4-Flash-0731's 1,048,576 tokens. DeepSeek-V4-Flash-0731 can generate longer responses up to 65,536 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 DeepSeek-V4-Flash-0731 does not.
Grok 4 Fast can handle both text and other forms of data like images, making it suitable for multimodal applications.
DeepSeek-V4-Flash-0731
Grok 4 Fast
License
Usage and distribution terms
DeepSeek-V4-Flash-0731 is licensed under MIT, while Grok 4 Fast uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
DeepSeek-V4-Flash-0731 was released on 2026-07-31, while Grok 4 Fast was released on 2025-08-28.
DeepSeek-V4-Flash-0731 is 11 months newer than Grok 4 Fast.
Jul 31, 2026
6 days ago
11mo newerAug 28, 2025
11 months ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
DeepSeek-V4-Flash-0731 is available from DeepInfra, Fireworks, Novita. Grok 4 Fast is available from xAI.
DeepSeek-V4-Flash-0731
Grok 4 Fast
Outputs Comparison
Key Takeaways
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against DeepSeek-V4-Flash-0731 and Grok 4 Fast side-by-side, then vote on the output you prefer.
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FAQ
Common questions about DeepSeek-V4-Flash-0731 vs Grok 4 Fast.