Claude Sonnet 4.5 vs Step3: side-by-side summary

Claude Sonnet 4.5 and Step3 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Claude Sonnet 4.5, from Anthropic, has a 1,000,000-token context window and is priced at $3/M tokens input, $15/M tokens output on OpenRouter.

Step3, from stepfun-ai, has a 65,536-token context window and is priced by the provider serving it on OpenRouter.

Context window

• Claude Sonnet 4.5: 1,000,000 tokens
• Step3: 65,536 tokens

Price

• Claude Sonnet 4.5: $3/M tokens input, $15/M tokens output
• Step3: Pricing varies by provider

Provided by

• Claude Sonnet 4.5: Anthropic
• Step3: stepfun-ai

• Claude Sonnet 4.5 model details, providers and pricing
• Step3 model details, providers and pricing