Claude
Also known as: Claude AI, Claude models
Claude launched publicly in March 2023. With the Claude 3 generation in March 2024, Anthropic formalized a three-tier naming structure: Haiku for speed and cost, Sonnet for balanced performance, and Opus for maximum capability. Each tier targets a different cost-performance point, and the naming has stayed consistent through the Claude 4.x generation. The family is built using Constitutional AI, Anthropic's technique for training models to follow a structured set of ethical principles rather than relying on extensive human feedback alone.
As of May 2026, the active Claude 4.x lineup includes Claude Opus 4.8 (released May 28, 2026, the most capable model for complex reasoning, agentic coding, and long-running professional work), Claude Sonnet 4.6 (the balanced daily-driver model preferred by most developers for its combination of capability and cost), and Claude Haiku 4.5 (the lightweight option for high-volume, latency-sensitive tasks). All current Claude models support text and image input. Older Claude 4.0 and 4.1 variants were retired in April 2026.
Beyond the API, Claude powers a wide range of Anthropic product surfaces including Claude.ai, Claude Code (agentic coding), Claude Cowork (collaborative workspaces), and integrations into Office applications. A separate model called Claude Mythos Preview ships through Project Glasswing as an invitation-only research model for defensive cybersecurity work. The Claude family is also available on Amazon Bedrock, Vertex AI, and Microsoft Foundry.