Haiku 4.5 at a Glance

Anthropic shipped Claude Haiku 4.5 a few weeks ago. It's built for a different use case than Sonnet 4.5: you trade deeper reasoning for speed and cost. For most things, that's the right trade.

The Numbers

Haiku is 3.75x cheaper across the board. Sub-200ms latency too—Sonnet takes 500-800ms. That matters if you're building anything that needs to feel responsive.

Real numbers: a small support chatbot might cost $5-20/month on Haiku instead of $50-150/month on Sonnet. For high-volume workloads, the gap only gets bigger.

What Haiku's Good For

Coding work? Haiku matches Sonnet 4 on most tasks. I use it for small refactors, code review, and debugging. The speed makes it feel snappier than pulling out Sonnet. For real-time pair programming or customer support, it's the obvious choice. You'd use Sonnet if you need complex reasoning or writing that demands nuance.

The Catch

All three recent Claude models (Haiku, Sonnet 4.5, Opus 4.1) have a knowledge cutoff at January 2025. No awareness of new frameworks, libraries, or breaking changes after that. If you're working with bleeding-edge stuff, you'll need to provide context in your prompt. For established patterns and refactoring? Fine.

Worth Using

Haiku makes LLM integration practical for projects where you'd normally skip it because cost adds up. You can afford to be generous with API calls. It's not going to impress anyone with reasoning power, but it doesn't need to. It's fast, cheap, and genuinely solid for what most developers actually do.

Related posts:

• Claude Code's Strengths and Weaknesses in March 2025 - See how Haiku compares to other Claude tools
• GPT-4.1: SWE-bench Performance - Compare Haiku to GPT-4.1 on coding benchmarks
• The True Cost of AI - Understand AI pricing across different models and services