Claude Haiku 5.5
Anthropic's fastest small model, built for high-volume work like summarization, subagents and browser use. $0.50 / $2.50 per 1M tokens (prompts ≤100K).
Verdict: Builders running subagents or high-volume tasks on a budget.
Claude API (Anthropic)
Claude models for coding and agents.
Anthropic · checked Oct 22, 2026
What it is
The Claude Platform API serves Opus 5.5, Sonnet 5.5, Haiku 5.5 and Fable 5.1, plus Managed Agents, web search and code execution tools.
Use cases
- →Powering coding agents
- →Long-running agentic tasks
- →High-quality tool use
Pros
- +Top coding/agent models
- +Cheap cache reads for agent loops
- +Available on AWS, Google Cloud, Azure
Cons
- −Premium models aren't cheap
- −Breaking API changes between generations
Where it ranks
- #1 Best LLM APIs & Model Routers
Top coding/agent models (Opus 5.5 at $4/$20 per M tokens) with cheap cache reads for agent loops.
On the Release Radar
Claude Sonnet 5.5
Clear upgrade over Sonnet 5: 30%+ faster and up to 30% cheaper for most work. API $2 / $10 per 1M tokens.
Verdict: Default model choice for most coding agents and AI features.
Claude Opus 5.5
Leads in agentic coding; performs at Fable 5.1 level on most work and costs ~40% less to run than Opus 5. $4 / $20 per 1M tokens, cache reads $0.20.
Verdict: Long-running coding agents and big migrations.
Claude Mythos and Fable 5.1
Anthropic's most advanced models for coding and knowledge work. Fable 5.1 API $10 / $50 per 1M tokens.
Verdict: Hardest problems only; Opus 5.5 is cheaper for most builders.
FAQ
How much does Claude API (Anthropic) cost?
Per million tokens (input/output): Opus 5.5 $4/$20, Sonnet 5.5 $2/$10, Haiku 5.5 $0.50/$2.50, Fable 5.1 $10/$50. Prompt-cache reads discounted. (As checked on 2026-10-22; confirm on https://claude.com/pricing.)
What is Claude API (Anthropic) best for?
#1 in Best LLM APIs & Model Routers: Coding agents and tool-heavy apps.
What are the best alternatives to Claude API (Anthropic)?
OpenAI API (GPT-6 family models via API); Gemini API (Gemini models via AI Studio and the Gemini API); OpenRouter (One API for 500+ models across 80+ providers).
Is Claude API (Anthropic) open source?
No, Claude API (Anthropic) is a commercial product.