Claude model IDs

A Claude model ID is the model family and version in lowercase, joined with hyphens: Claude Sonnet 5.5 is claude-sonnet-5-5. The table opens on every Claude model you can still call on the Claude API, current and legacy, plus the one deprecated model that is still running. Click an ID to copy it.

Where the ID goes

Pass it as model in a Messages API call. This is Anthropic's Python quickstart:

import anthropic

client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-opus-5-5",
    max_tokens=1000,
    messages=[
        {
            "role": "user",
            "content": "What should I search for to find the latest developments in renewable energy?",
        }
    ],
)

for block in message.content:
    if block.type == "text":
        print(block.text)

Dateless IDs, dated IDs and aliases

Claude IDs come in two shapes. From the 4.6 generation on, the ID has no date (claude-opus-4-6, claude-opus-5-5) and is itself a fixed snapshot, not a pointer to "the latest Opus". Earlier models have a dated ID such as claude-opus-4-5-20251101, plus a shorter alias, claude-opus-4-5, that resolves to it. The Alias column shows the alias where one exists.

When this is and isn't the right page

• Right page: you are calling the Claude API (or Claude on Google Cloud, which uses the same IDs) and need the string for a specific Claude model, or want to check whether yours has a retirement date.
• Not quite: on Amazon Bedrock, add the anthropic. prefix, and check Anthropic's models overview for older models, which use a different Bedrock ID.
• Not this page: Claude Mythos models are left out: Anthropic lists them as limited availability for verified organizations, so most API keys cannot call them.
• Not this page: you are comparing Claude with GPT or Gemini. Use the all-provider list or the AI cost calculator.