GPT-5.1 Chat vs Grok 4.1 Fast: side-by-side summary

GPT-5.1 Chat and Grok 4.1 Fast are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

GPT-5.1 Chat, from OpenAI, has a 128,000-token context window and is priced by the provider serving it on OpenRouter.

Grok 4.1 Fast, from SpaceXAI, has a 2,000,000-token context window and is priced by the provider serving it on OpenRouter.

Context window

• GPT-5.1 Chat: 128,000 tokens
• Grok 4.1 Fast: 2,000,000 tokens

Price

• GPT-5.1 Chat: Pricing varies by provider
• Grok 4.1 Fast: Pricing varies by provider

Provided by

• GPT-5.1 Chat: OpenAI
• Grok 4.1 Fast: SpaceXAI

• GPT-5.1 Chat model details, providers and pricing
• Grok 4.1 Fast model details, providers and pricing