Model retirements · Gemini API · checked

gemini-3-pro-preview (Gemini API) shutdown date: 9 March 2026

Google listed gemini-3-pro-preview on the Gemini API for shutdown no earlier than 9 March 2026 (the earliest date Google gives) and recommends gemini-3.1-pro-preview as the replacement. No price ratio: the retiring model is not listed on the Gemini API pricing page when checked on 8 October 2026, so no ratio is given. Google's deprecation page documents no API changes for this move. It can no longer be asked, so its answers cannot be recorded now; compare the replacement against the outputs you still have.

Find every place your code and config name it, with this page's facts beside each:

$ npx --allow-git=root github:agentwares/model-migrate scan

npx --allow-git=root github:agentwares/model-migrate scan lists every model ID in your code and config that has a shutdown date, with its replacement, price ratio and this page's link. It needs no account and no API key, reads your files on your machine and sends nothing; its one request fetches this data. Free and MIT licensed.

The facts

Platform
Gemini API
Model ID
gemini-3-pro-preview
Announced
no date on the page
Shutdown
9 March 2026The earliest possible date; Google says it will confirm the exact date in advance.
Recommended replacement
gemini-3.1-pro-preview
List price per million tokens, input / output
The retiring model is not listed on the Gemini API pricing page when checked on 8 October 2026, so no ratio is given.

Prices are the provider's list prices for the standard tier, text input and the shortest context tier. A per-token ratio leaves out how many tokens each model spends on the same prompt; only your own prompts show that.

What changes when you move

Google's deprecation page lists no parameter or API changes for this move. The model's answers still change: a replacement is a different model.

How to test the replacement on your own prompts

  1. Find every call that names gemini-3-pro-preview: npx --allow-git=root github:agentwares/model-migrate scan prints each file and line.
  2. gemini-3-pro-preview can no longer answer, so use the outputs you already logged, or your current outputs, as the baseline.
  3. Run the same prompts on gemini-3.1-pro-preview, a cheaper sibling and a model from another provider, and compare with checks that need no judge: exact or normalised match, JSON validity and schema, tool-call names and arguments, refusals and length. npx --allow-git=root github:agentwares/model-migrate compare does this on your keys.
  4. Price the move with the token counts each provider reports for those prompts, not with the list price alone; compare reports the cost per 1,000 calls.

Keep testing until the date

capture and compare run on your keys and keep everything on your machine. To re-run the same prompts against your own endpoint whenever a provider ships a model, with the history kept, npx --allow-git=root github:agentwares/model-migrate export --agentcheck writes them as traces that agentcheck imports onto a target you monitor there. On its Pro plan they become checks that re-run when a provider ships a model, with 90 days of history.

Migration watch is not built. It would re-run your captured prompts on each replacement and each new model until 9 March 2026, with no endpoint needed, and email you what changed. If you would pay for that, say so with one click. The click is counted; nothing else is sent or stored.

Other Gemini API retirements

Every announced shutdown, by date

Sources

Built only from the providers' own pages. No vendor intent is implied: a date is what the page says on the day it was read. Data: /models/retirements.json.

model-migrate is a free tool from agentcheck, which re-runs an agent's checks when a provider ships a model and replays recorded traces nightly, so a model change that breaks it arrives as one diff by email.