AnthropicText generationReleased September 28, 2026

Claude Sonnet 5.5

Name: Claude Sonnet 5.5
Brand: Anthropic
SKU: claude-sonnet-5-5
Availability: InStock

Claude Sonnet 5.5 costs $2 per 1M input tokens and $10 per 1M output tokens on LLM API, with a 1M-token context window.

Pricing

Lowest price among 3 providers, after discounts.

Claude Sonnet 5.5 prices on LLM API
Input	$2	per 1M tokens
Output	$10	per 1M tokens
Cache read	$0.1	per 1M tokens
Cache write, 5 minutes	$2.5	per 1M tokens
Cache write, 1 hour	$4	per 1M tokens

Providers

Prices after each provider’s discount; the lowest in bold.

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Providers of Claude Sonnet 5.5 on LLM API

Anthropic	$2	$10	$0.1	1M	128K
AWS Bedrock	$2	$10	$0.1	1M	128K
ComputeBase	$2	$10	$0.1	1M	128K

Features

“Some providers”: not every provider of this model supports it.

ToolsYes
Parallel tool callsNo
Image inputYes
ReasoningYes
Levels: low, medium, high, xhigh, max · default medium
Prompt cachingYes
Structured outputsSome providers
JSON modeSome providers
StreamingYes
Web searchYes

Call Claude Sonnet 5.5

POST /v1/messagesSet LLMAPI_KEY to your LLM API key.Anthropic Messages docs

import os

import anthropic

client = anthropic.Anthropic(
    base_url="https://api.llmapi.ai",
    api_key=os.environ["LLMAPI_KEY"],
)

message = client.messages.create(
    model="claude-sonnet-5-5",
    max_tokens=16000,
    messages=[{"role": "user", "content": "Hello"}],
)
for block in message.content:
    if block.type == "text":
        print(block.text)

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  baseURL: "https://api.llmapi.ai",
  apiKey: process.env.LLMAPI_KEY,
});

const message = await client.messages.create({
  model: "claude-sonnet-5-5",
  max_tokens: 16000,
  messages: [{ role: "user", content: "Hello" }],
});
for (const block of message.content) {
  if (block.type === "text") console.log(block.text);
}

curl https://api.llmapi.ai/v1/messages \
  -H "x-api-key: $LLMAPI_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-sonnet-5-5",
    "max_tokens": 16000,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

POST /v1/chat/completionsSet LLMAPI_KEY to your LLM API key.Chat Completions docs

import os

from openai import OpenAI

client = OpenAI(
    base_url="https://api.llmapi.ai/v1",
    api_key=os.environ["LLMAPI_KEY"],
)

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

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.llmapi.ai/v1",
  apiKey: process.env.LLMAPI_KEY,
});

const response = await client.chat.completions.create({
  model: "claude-sonnet-5-5",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(response.choices[0].message.content);

curl https://api.llmapi.ai/v1/chat/completions \
  -H "Authorization: Bearer $LLMAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-5-5",
    "messages": [{"role": "user", "content": "Hello"}]
  }'

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Prices synced October 27, 2026.