Question 1

Is Claude 3.5 Sonnet still available on the API?

Accepted Answer

No. Claude 3.5 Sonnet was retired by Anthropic on 2025-10-28. Requests to this model id return an error from the upstream API. Migrate to Claude Sonnet 4.6 for continued service.

Question 2

What should I use instead of Claude 3.5 Sonnet?

Accepted Answer

Anthropic's recommended replacement is Claude Sonnet 4.6. It is the same provider's current generation in the same tier, available at https://1vy.ai/models/claude-sonnet-4-6.

Question 3

Why does the page still exist if the model is retired?

Accepted Answer

So existing links and search results continue to land on a useful page. The pricing shown is the final list price before retirement (kept for historical reference); the model itself does not accept new requests.

Direction	Price / 1M tokens (USD)
Input	$3.45
Output	$17.25

Claude 3.5 Sonnet

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