Compare GPT-5.5 Pro from OpenAI and Step 3.7 Flash from stepfun on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.
GPT-5.5 Pro and Step 3.7 Flash are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
GPT-5.5 Pro, from OpenAI, has a 1,050,000-token context window and is priced at $30/M tokens input, $180/M tokens output on OpenRouter.
Step 3.7 Flash, from stepfun, has a 262,144-token context window and is priced at $0.16/M tokens input, $0.92/M tokens output on OpenRouter.