Claude Sonnet 4.6 API

Overview

Claude Sonnet 4.6 hits the sweet spot for most production workloads. It's fast enough for real-time apps and smart enough for genuinely hard tasks, at one-fifth the price of Opus. For most teams, this is the default.

What Claude Sonnet 4.6 is best for

• Coding assistants and IDE integrations
• Content generation at scale
• Data processing and extraction
• Most production chat and agent workloads
• 🧠 Extended thinking available

Strengths and tradeoffs

Strengths: Excellent quality-to-cost ratio, 200K context, extended thinking, fast responses.

Tradeoff: Slightly behind Opus on the very hardest reasoning tasks, but the gap is small for everyday work.

Pricing

Estimate your own usage with the API cost calculator or count tokens with the token counter.

Quick start (Python)

Claude Sonnet 4.6 runs through KissAPI's OpenAI-compatible endpoint, so any OpenAI SDK works. Just change the base URL and model id:

from openai import OpenAI

client = OpenAI(
    api_key="YOUR_KISSAPI_KEY",
    base_url="https://api.kissapi.ai/v1",
)

resp = client.chat.completions.create(
    model="claude-sonnet-4-6",
    messages=[{"role": "user", "content": "Explain async/await in one paragraph."}],
)
print(resp.choices[0].message.content)

Works with Cursor, Claude Code, Cline, Aider, and any OpenAI-compatible client.

Frequently asked questions

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