Claude Haiku 4.5 vs o3 Pro

Claude Haiku 4.5

Anthropic

Claude Haiku 4.5, released by Anthropic in October 2025, is a fast, efficient large language model from the Claude 4.5 family optimized for high-throughput, low-latency workloads. It features a 200K token context window, 64K maximum output tokens, native image understanding, and extended thinking capabilities. Haiku 4.5 targets latency-sensitive applications such as real-time assistants, document classification, and lightweight agentic tasks where rapid response times are a primary requirement.

o3 Pro

OpenAI

OpenAI o3-pro, released by OpenAI in June 2025, is an extended reasoning model from the o3 family that applies more compute per response to deliver deeper, more thorough answers on complex problems. It features a 200K token context window, 100K maximum output tokens, and vision capabilities. o3-pro targets research-grade reasoning tasks, extended coding sessions, and applications where accuracy on difficult problems justifies higher inference cost and latency.