Key Info

Claude Sonnet 5.5, the second model in Anthropic's Claude 5.5 family, is now available on OpenRouter with 1M context at $2/M input and $10/M output.

Highlights

  • Described as significantly smarter than Sonnet 5 with much clearer writing
  • More than 30% faster and up to 30% cheaper for most workloads
  • 1M context window priced at $2/M input and $10/M output, unchanged from Sonnet 5
  • Positioned as the second model in the Claude 5.5 family