xAI Launches Grok 4 Fast

xAI, has released a new model called Grok 4 Fast. The system delivers the same high-level intelligence as the company’s flagship Grok 4 model, but at a fraction of the cost.

Grok 4 Fast is being hailed as a major step in making advanced AI tools affordable for businesses, developers, and everyday users.

Key Features

Cost Efficiency

• The most striking feature of Grok 4 Fast is its 98% lower cost compared to Grok 4.
• xAI says the new system uses 40% fewer “thinking tokens”  the computational resources needed for reasoning. That means businesses can access powerful AI reasoning at just a fraction of the price.
• Pricing reflects this massive efficiency improvement.
• Grok 4 Fast costs only $0.20 per million input tokens and $0.50 per million output tokens, making it one of the cheapest advanced AI services available today.
• Independent analysts confirmed these claims, noting that Grok 4 Fast performs on par with Google’s Gemini 2.5 Pro while costing 25 times less.

Unified Architecture: Two Modes in One

• Another major highlight is the model’s unified architecture. While competitors often build separate AI systems for reasoning and fast response, Grok 4 Fast combines both into one.
• It can switch seamlessly between a reasoning mode for solving complex problems and a non-reasoning mode for fast, simple replies.
• This design makes Grok 4 Fast both flexible and efficient, offering users the right balance between speed and intelligence depending on their needs.
• Engineers at xAI achieved this by using large-scale reinforcement learning to increase what they call “intelligence density” — packing more problem-solving capability into fewer resources.

Technical Specs and Speed

• Grok 4 Fast comes with a 2 million token context window, allowing it to handle massive inputs such as long legal documents, full research reports, or entire software codebases.
• It also delivers 344 tokens per second in output speed nearly 2.5 times faster than GPT-5 through API connections.
• This means users get quick answers even when the model is running in reasoning mode.

Benchmarks Performance

Despite being cheaper, Grok 4 Fast delivers top-tier results across global AI benchmarks:

85.7% on GPQA Diamond, 92% on AIME 2025, 93.3% on HMMT 2025, 80% pass rate on Live CodeBench for coding tasks.

On LMArena, a competitive AI evaluation platform, Grok 4 Fast ranked first place in search tasks and eighth in text-based evaluations.

These scores put it close to or even better than more expensive models.

Availability

xAI has rolled out Grok 4 Fast to all users immediately, including those on the free tier.

It is available on grok.com, as well as through iOS and Android mobile apps.

For developers, it can be accessed through the xAI API, OpenRouter, and the Vercel AI Gateway.

As a promotional offer, Grok 4 Fast is currently available for free on OpenRouter and Vercel, giving developers a chance to test its capabilities without paying anything.

Users can choose between two versions:

• grok-4-fast-reasoning for complex tasks.
• grok-4-fast-non-reasoning for quick responses.

Industry Impact

The release of Grok 4 Fast comes at a time when the AI market is highly competitive.

Rivals like Google are working on Gemini upgrades, while Anthropic is pushing Claude improvements. But xAI’s focus on affordability could change the game by opening up AI access to small businesses, schools, and individuals who were priced out before.

By lowering costs so dramatically, Musk’s company is making frontier-level AI more accessible, potentially driving adoption across healthcare, education, law, and small business operations.

xAI’s Roadmap and Development

The launch follows major changes at xAI, including the layoff of around 500 data annotation workers as the company pivots toward AI tutoring roles.

Despite these shifts, xAI has continued to build its tech using the Colossus cluster, which runs on 200,000 GPUs and powers its large-scale reinforcement learning training.

Elon Musk has positioned xAI as a strong competitor to OpenAI and Google.

The company also benefits from its integration with X (formerly Twitter), giving it access to real-time social data to improve its AI.

News Gist

xAI, founded by Elon Musk, has launched Grok 4 Fast, a powerful AI model that’s 98% cheaper than its predecessor.

With faster speed, 2M token context, and unified reasoning, it makes high-quality AI more affordable for businesses and individuals.

FAQs

Q1. What is Grok 4 Fast?

It’s xAI’s new AI model that delivers reasoning power similar to Grok 4 but at 98% lower cost.

Q2. How cheap is Grok 4 Fast?

Pricing is just $0.20 per million input tokens and $0.50 per million output tokens, making it one of the most affordable advanced AI systems.

Q3. How fast is the model?

Grok 4 Fast generates 344 tokens per second, nearly 2.5x faster than GPT-5 via API.

Q4. What’s special about its design?

It has a unified architecture, switching between reasoning and quick-response modes without needing separate models.

Q5. Where is Grok 4 Fast available?

It’s accessible now via grok.com, iOS/Android apps, xAI API, OpenRouter, and Vercel AI Gateway.