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Claude API

The API for accessing Anthropic's Claude models programmatically.

What is Claude API?

The Claude API is Anthropic's programmatic interface to the Claude family (Haiku, Sonnet, Opus). It is the second-most-used LLM API in production Indian Gen AI work, often preferred for long-context analysis and structured reasoning.

Key features: **200K context** (Opus has up to 1M), **tool use** (similar to function calling), **prompt caching** (up to 90% discount on long repeated prefixes), **vision**, **code execution** (a sandbox the model can run code in).

Claude is often chosen over GPT for: legal/financial document analysis (better long-context recall), code generation (Opus is exceptionally strong), and structured extraction at scale. Pricing is comparable to OpenAI.

Why this matters

Knowing both Claude AND OpenAI APIs — and the judgement of which to pick per task — is what senior Gen AI engineers are paid for.

Real-world example (India)

A Hyderabad-based contract-review platform routes short queries to Claude Haiku (cheap, fast) and long analyses to Claude Opus 4 with 1M context (deep, accurate). The two-model routing dropped cost 80% versus running everything on Opus.