Overview
Claude Sonnet 4.5 vs GPT-5.1-Codex: side-by-side summary
Claude Sonnet 4.5 and GPT-5.1-Codex 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.
GPT-5.1-Codex, from OpenAI, has a 400,000-token context window and is priced at $1.25/M tokens input, $10/M tokens output on OpenRouter.
- Context window
- Claude Sonnet 4.5: 1,000,000 tokens
- GPT-5.1-Codex: 400,000 tokens
- Price
- Claude Sonnet 4.5: $3/M tokens input, $15/M tokens output
- GPT-5.1-Codex: $1.25/M tokens input, $10/M tokens output
- Provided by
- Claude Sonnet 4.5: Anthropic
- GPT-5.1-Codex: OpenAI