Compare GPT-5.1 Chat from OpenAI and Grok 4 Fast from SpaceXAI on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.
GPT-5.1 Chat and Grok 4 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 Fast, from SpaceXAI, has a 2,000,000-token context window and is priced by the provider serving it on OpenRouter.