Anthropic Reasoning

Claude 3.7 Sonnet Thinking

Legacy Claude 3.7 Sonnet with thinking mode

200K Context window

Text + Vision Modalities

Reasoning Specialty

Yes Streaming

Get API key — free View docs →

Model ID claude-3-7-sonnet-20250219-thinking /v1/chat/completions

Our pricing

Input tokens per 1M tok

$2.40

Output tokens per 1M tok

$12.00

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 3.7 Sonnet 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-3-7-sonnet-20250219-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-3-7-sonnet-20250219-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-3-7-sonnet-20250219-thinking","messages":[{"role":"user","content":"Hello!"}]}

Highlights

Built for production.

Reasoning

Complete guide

Everything about
Claude 3.7 Sonnet Thinking.

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

By Anthropic 2 min read Updated May 2026

Legacy Claude 3.7 Sonnet with thinking mode

Overview

Claude 3.7 Sonnet 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 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 3.7 Sonnet Thinking delivers industry-leading performance and reliability.

Key Specifications

Specification	Details
Model Name	Claude 3.7 Sonnet Thinking
Provider	Anthropic
Category	AI Reasoning Model
Model Type	Reasoning
Context Window	200K

Pricing

Input: $2.4/M tokens
Output: $12/M tokens

Key Features & Capabilities

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 3.7 Sonnet Thinking best used for?

Claude 3.7 Sonnet Thinking excels at reasoning, making it ideal for professional and enterprise applications.

Who developed Claude 3.7 Sonnet Thinking?

Claude 3.7 Sonnet Thinking was developed by Anthropic, a leading AI research and development company.

How do I integrate Claude 3.7 Sonnet Thinking into my application?

You can integrate Claude 3.7 Sonnet 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 3.7 Sonnet Thinking?

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

Ready to ship? Start using Claude 3.7 Sonnet Thinking in under 30 seconds.

Get free API key