xAI: Grok 4 Fast API Price, Cost Calculator & Specs

At $0.20/$0.50 per 1M tokens with a 2M context window, this is where Grok 4 Fast pulls ahead of the pack. Most models in this price range cap out at 128K-256K tokens—like MiniMax M2's 256K—forcing you to chunk long documents and lose context. With 2M tokens, you can feed entire reports, conversation histories, or codebases without the engineering overhead of chunking strategies. The price is production-ready: not cheap enough to be careless, but affordable enough to scale. For a $30/mo SaaS subscription, you can handle 50-100K tokens per user monthly without margin erosion. Enable the reasoning parameter selectively for complex queries since it triples output costs—use it on the 20% of requests that matter, not the routine 80%.

Best For:

Bulk Content Processing: With its massive 2M context window, this shines for processing long documents, reports, or conversation history where other models force you to chunk and lose context. Perfect for document analysis tools, research assistants, or any workflow that needs to "read everything at once."

Multi-modal Document Understanding: When your SaaS needs to analyze both text and images together—like processing receipts, forms, or visual reports—Grok 4 Fast's text+image inputs make it a solid workhorse. The cost is reasonable enough for production use cases like invoice processing or visual data extraction.

Selective Reasoning Tasks: Use the reasoning parameter strategically for your most complex 20% of queries, but route the remaining 80% to standard mode. This gives you the benefits of advanced reasoning when it matters, without burning through your COGS on routine tasks.