Anthropic Reasoning Popular

Claude Haiku 4.5 Thinking

Thinking version of fast Haiku model

200K Context window

Text + Vision Modalities

Reasoning Specialty

Yes Streaming

Get API key — free View docs →

Model ID claude-haiku-4-5-20251001-thinking /v1/chat/completions

Our pricing

Input tokens per 1M tok

$0.800

Output tokens per 1M tok

$4.00

Pay-as-you-go · No minimums · Cancel anytime

OpenAI-compatible ( api.belugapi.com/v1)

Start for free →

No credit card required to test

Capabilities

What Claude Haiku 4.5 Thinking
can do for you.

Native API parity with the official provider — every feature surfaced one-to-one.

Streaming

Server-sent events out of the box

Vision

Analyze images, charts & documents

Reasoning

Deep chain-of-thought for hard tasks

Long context

200K+ tokens of working memory

Integration

2-line migration.
Zero friction.

BelugAPI is 100 % compatible with the OpenAI SDK. Point base_url to our endpoint and you're done — no refactoring, no learning curve.

Same request & response schema

Python · Node.js · REST · Go · Ruby

Streaming, tool-calling, structured output

Automatic failover & load balancing

Python

from openai import OpenAI

client = OpenAI(
  api_key=bel-your-key,
  base_url=https://api.belugapi.com/v1
)

response = client.chat.completions.create(
  model=claude-haiku-4-5-20251001-thinking,
  messages=[{"role": user, "content": Hello!}]
)
print(response.choices[0].message.content)

Node.js

import OpenAI from openai;

const client = new OpenAI({
  apiKey:  bel-your-key,
  baseURL: https://api.belugapi.com/v1,
});

const res = await client.chat.completions.create({
  model:    claude-haiku-4-5-20251001-thinking,
  messages: [{ role: user, content: Hello! }],
});
console.log(res.choices[0].message.content);

cURL

curl https://api.belugapi.com/v1/v1/chat/completions \
  -H Authorization: Bearer bel-your-key \
  -H Content-Type: application/json \
  -d {"model":"claude-haiku-4-5-20251001-thinking","messages":[{"role":"user","content":"Hello!"}]}

Highlights

Built for production.

Fast reasoning

Complete guide

Everything about
Claude Haiku 4.5 Thinking.

Specifications, pricing, capabilities, and integration tips — kept up to date with every Anthropic release.

By Anthropic 2 min read Updated May 2026

Thinking version of fast Haiku model

Overview

Claude Haiku 4.5 Thinking is a cutting-edge ai reasoning model developed by Anthropic, designed to push the boundaries of artificial intelligence-powered content generation.

This model excels in fast reasoning, making it a top choice for professionals seeking high-quality, scalable AI solutions. Whether you're building production applications, researching new AI capabilities, or creating stunning visual content, Claude Haiku 4.5 Thinking delivers industry-leading performance and reliability.

Key Specifications

Specification	Details
Model Name	Claude Haiku 4.5 Thinking
Provider	Anthropic
Category	AI Reasoning Model
Model Type	Reasoning
Context Window	200K

Pricing

Input: $0.8/M tokens
Output: $4/M tokens

Key Features & Capabilities

Fast Reasoning: Advanced capability for professional-grade output.

Use Cases & Applications

Complex problem solving
Scientific research assistance
Mathematical computation
Multi-step workflow automation

Frequently asked questions

What is Claude Haiku 4.5 Thinking best used for?

Claude Haiku 4.5 Thinking excels at fast reasoning, making it ideal for professional and enterprise applications.

Who developed Claude Haiku 4.5 Thinking?

Claude Haiku 4.5 Thinking was developed by Anthropic, a leading AI research and development company.

How do I integrate Claude Haiku 4.5 Thinking into my application?

You can integrate Claude Haiku 4.5 Thinking via its official API endpoint using standard HTTP requests with your API key. SDKs are available for Python, JavaScript, and other languages.

What is the pricing model for Claude Haiku 4.5 Thinking?

Pricing is based on input. Check the pricing section above for detailed rates.

Ready to ship? Start using Claude Haiku 4.5 Thinking in under 30 seconds.

Get free API key