Model retirements · Gemini API · checked

gemini-2.5-flash-preview-09-25 (Gemini API) shutdown date: 17 February 2026

Google listed gemini-2.5-flash-preview-09-25 on the Gemini API for shutdown no earlier than 17 February 2026 (the earliest date Google gives) and recommends gemini-3.6-flash 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 documents two changes that can break code: a temperature below 1.0 may cause looping; sending thinking_level and thinking_budget together returns a 400 error. 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-2.5-flash-preview-09-25
Announced
no date on the page
Shutdown
17 February 2026The earliest possible date; Google says it will confirm the exact date in advance.
Recommended replacement
gemini-3.6-flash
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

How to test the replacement on your own prompts

  1. Find every call that names gemini-2.5-flash-preview-09-25: npx --allow-git=root github:agentwares/model-migrate scan prints each file and line.
  2. gemini-2.5-flash-preview-09-25 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-3.6-flash, 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.
  5. Make the changes listed above before you switch.

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 17 February 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.

Also shutting down on 17 February 2026

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.