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Playbook for makers · Forced move · free while in beta

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Claude Sonnet 4.5 retires on the Claude API on November 30, 2026

Readers can stay on Claude Platform: they change a setting or plan. Help the ones who would rather leave.

45 days left · November 30, 2026 · Public page

Low switching pressure44/100

An estimate from the deadline, cost, discussion and need to move. It is not a product rating.

What goes into it

Confidence: medium.

deadline24/30
money14/25
attention0/25
audience0/12
force6/8
  • Hard deadline in 45 days.
  • The change is forced: it reaches users even if they wait.

  1. 1 Related discussions

    Only threads tied to this event that talk about leaving, moving or prices. Saved, not live. Check the date and read the thread before replying.

    No live threads yet.

  2. 2 What people ask

    No common questions yet.

  3. 3 Reply templates

    Answer the question first. Link only if it helps. Always keep the disclosure line. Never post the same text twice.

    Helpful first
    Sorry you have to deal with this. You can stay on Claude Platform. Here is what to change before November 30, 2026:

1. Find calls to the old model. Search your code and settings for claude-sonnet-4-5-20250929.
2. Switch to claude-sonnet-5-5. Change the model name. Read Anthropic's migration guide for changed behavior.
3. Test before November 30. Run your usual prompts and check output, tool use and cost.

If they would rather leave, describe a verified way <your product> can help: <your link>
[Disclosure: I build <your product>.]
    Short answer
    You have until November 30, 2026. You can stay on Claude Platform. First: find calls to the old model. Then switch to claude-sonnet-5-5.
Happy to help if you get stuck.
[Disclosure: I build <your product>.]

  4. 4 Switch-page builder

    Create a draft “Switch from Claude Platform” page. Add your product, review every claim, then copy HTML or Markdown. Your product claims need your own evidence.

    • Add your product name to replace “Your product”.
    Preview

    Switch from Claude Platform to Your product

    Claude Sonnet 4.5 on the Claude API: a change is due by November 30. You can stay on Claude Platform. If you would rather leave, here is how to move to Your product.

    What changes at Claude Platform

    Anthropic plans to retire Claude Sonnet 4.5 on November 30, 2026. Requests to it will fail after that. Anthropic names claude-sonnet-5-5 as the replacement.

    • Tentative retirement date: November 30, 2026 (Anthropic)
    • Model: claude-sonnet-4-5-20250929 (Claude Sonnet 4.5) (Anthropic)
    • Developers told: September 30, 2026 (Anthropic)
    • Replacement: claude-sonnet-5-5 (Anthropic)
    • After retirement: Requests to the model will fail (Anthropic)
    • Where this date applies: The Claude API, Claude Platform on AWS and Microsoft Foundry (Anthropic)
    • Amazon Bedrock and Google Cloud: Set their own retirement dates (Anthropic)
    • Apps that call Claude Sonnet 4.5: Requests fail after November 30, 2026 (Anthropic)

    You can stay on Claude Platform if you make the change. This page is for people who would rather leave.

    What Your product gives you

    Write two or three short lines here. Say what Your product does, who it is for, and what it costs. Use only facts you can show.

    How to move from Claude Platform to Your product

    1. Save what you need from Claude Platform. Keep a copy before you cancel anything.
    2. Import into Your product. Say which files you accept and how long an import takes.

    Tell readers the key date: November 30, 2026.

    Questions people ask

    If Your product has a direct answer to one of these, add it here. Keep it short and true.

    How to help new users settle in

    Send one short email. Say what changed, where to find you now, and what they need to do. Put the most important line first.

    If there is a date, send a short reminder a few days before it. Keep a copy of the list you sent it to.

    Sources

  5. 5 Search ideas to validate

    suggested, not measured Phrases people may search when a tool changes like this. We have no search volume data for them.

    • claude sonnet 4.5 on the claude api
    • claude platform alternative
    • claude platform alternatives
    • claude platform export
    • how to leave claude platform
    • switch from claude platform
    • claude platform migration
    • claude platform migration 2026