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Claude Opus 5.5 is built for long-running agentic coding and knowledge work with always-on thinking and five effort levels.

Provider: Anthropic

Category: text generation

Endpoint: /v1/chat/completions

Status: Available

Cost: --

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AnthropicText APIOnline

Claude Opus 5.5

Claude Opus 5.5 is built for long-running agentic coding and knowledge work with always-on thinking and five effort levels.

Use in your agent

API access

Endpoint

POST /v1/chat/completions

Base URL

https://api.hiapi.ai

OpenAI Chat Completions compatible. Use one HiAPI key across all available models.

Input price

4,040 Credits

/ 1M tokens

Output price

20,160 Credits

/ 1M tokens

Context

1M

context window

Max output

128K

output tokens

PlaygroundAPIPricingCapabilitiesOverview

Run settings

The Playground charges the signed-in account balance without requiring an extra API key. Server-side API calls still require a HiAPI API key.

Try Claude Opus 5.5

Ask a question to stream the answer and inspect token usage, latency, and estimated cost.

Claude Opus 5.5 API Quickstart

Call Claude Opus 5.5 with the OpenAI-compatible Chat Completions format. Copy a ready-to-use cURL, Python, or Node.js example below.

Code Example
API Endpoint:/v1/chat/completions
curl -X POST "https://api.hiapi.ai/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "claude-opus-5-5",
  "messages": [
    {
      "role": "user",
      "content": "请比较单体架构和微服务的取舍。"
    }
  ],
  "stream": false,
  "output_config": {
    "effort": "medium"
  }
}'

Tip: Replace YOUR_API_KEY with your actual API key from the API Keys page.

Compatible with the OpenAI Chat Completions format. Set the base URL, API key, and model name to get started.

Claude Opus 5.5 full API documentationManage API keysUse the same HiAPI key across all available models.

Claude Opus 5.5 API Pricing

Billing follows the input, output, and cache token categories actually reported in usage. All prices below are shown per 1 million tokens.

Input tokens
4,040 Credits/ 1M tokens

Prompts and context sent to the model

Output tokens
20,160 Credits/ 1M tokens

Responses and reasoning generated by the model

Cache read
200 Credits/ 1M tokens
Cache write
5,040 Credits/ 1M tokens
Cache write (1h)
8,064 Credits/ 1M tokens

Claude Opus 5.5 Model Specifications

These specifications reflect the current public HiAPI text request contract. Undisclosed capabilities are not inferred by the page.

Streaming
Supported
Tool calling
Supported
Structured JSON
Not disclosed
Reasoning
Supported
Input modalities
text
Output modalities
text
Reasoning efforts
low · medium · high · xhigh · max
Max output
128K

About Claude Opus 5.5

Claude Opus 5.5 is built for long-running agentic coding and knowledge work with always-on thinking and five effort levels.

HiAPI exposes this model through /v1/chat/completions. Test prompts and parameters in the Playground, then use the same HiAPI API key in your server application.

Provider
Anthropic
Endpoint
/v1/chat/completions
Context window
1M
Released
2026-09-22

How to Use Claude Opus 5.5

The Playground and API share the same model ID, so three steps take a tested prompt into production.

  1. Step 1

    Validate online

    Test the system prompt, output length, and model-supported reasoning options in the Playground.

  2. Step 2

    Manage API keys

    View an existing key or create another after signing in; one key works across all available models.

  3. Step 3

    Integrate your server

    Send requests to /v1/chat/completions and track cost with the usage object.

Need to compare models and billing tiers?View live pricing for all models

Frequently asked questions

What is Claude Opus 5.5?

Claude Opus 5.5 is Anthropic's model for long-running agentic coding and knowledge work. Anthropic documents a 1M-token context window and 128K maximum output.

Which endpoint and model ID should I use?

Use POST /v1/chat/completions with model=claude-opus-5-5.

Can I disable thinking?

No. Thinking is always on. Do not send thinking.type=disabled or a manual thinking budget; use output_config.effort instead.

Which effort levels are supported?

Use low, medium, high, xhigh, or max. Medium is the default.

How do tools and prompt caching work?

Use OpenAI-compatible tools with tool_choice=auto. Forced tool choices are unsupported. The initial HiAPI contract covers five-minute cache writes; verify writes and reads in usage and account logs.

How is usage billed?

Input, output, five-minute cache-write, and cache-read tokens use the live rates on the HiAPI model and pricing pages. Thinking tokens count as output.