Compare GPT-5 Pro from OpenAI and GPT-5.1 Chat from OpenAI 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 Pro and GPT-5.1 Chat are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
GPT-5 Pro, from OpenAI, has a 400,000-token context window and is priced at $15/M tokens input, $120/M tokens output on OpenRouter.
GPT-5.1 Chat, from OpenAI, has a 128,000-token context window and is priced by the provider serving it on OpenRouter.