On May 22, 2025, Anthropic officially unveiled its next-generation Claude 4 family—Claude Opus 4 and Claude Sonnet 4—marking a significant leap in large-language model capabilities. The announcement, delivered at Anthropic’s inaugural developer conference, emphasizes Claude Opus 4’s prowess in sustained, long-horizon tasks—capable of “focused effort” over several hours—and positions Anthropic in direct competition with OpenAI, Google, and other frontier AI developers .
The Claude 4 series comprises two variants:
- Claude Sonnet 4, available to both free-tier and paid users, serves as a drop-in upgrade from Sonnet 3.7, offering improved coding, math, and instruction-following performance.
- Claude Opus 4, reserved for paying customers and API partners, represents the family’s flagship model, delivering world-class coding capabilities and advanced reasoning. It is accessible via Anthropic’s API on Amazon Bedrock and Google Vertex AI at $15/$75 per million tokens for Opus 4 (input/output) and $3/$15 per million tokens for Sonnet 4.
