Claude Haiku 5.5 (EU)

Claude Haiku 5.5 is Anthropic's smallest and fastest model in the Claude 5.5 family, positioned for high-volume, cost-sensitive workloads where latency matters most. According to Anthropic, it is "our fastest, cheapest, and most capable small model yet," designed for classification, routing, extraction, and subagent tasks. The official comparison table confirms it carries the "Fastest" latency label among the Claude 5.5 lineup, beating Sonnet 5.5 in speed while remaining far less expensive than Opus 5.5 and Fable 5.1.

The model adopts the newer tokenizer introduced with Claude 4.7, which means roughly thirty percent more tokens are counted for the same text compared to Haiku 4.5. It supports adaptive thinking controllable via the effort parameter, with a default medium setting, and its thinking blocks remain scoped to the producing account or a linked one. As a small model aimed at scale, Claude Haiku 5.5 fits pipelines that need quick, cheap reasoning, structured output, and tool calling for delegation to larger Claude models when deeper analysis is required.