Nano Banana 2 and Pro reach GA: move from preview to stable IDs

The stable releases

On May 28, 2026, Google released stable Nano Banana 2 and Pro identifiers: gemini-3.1-flash-image and gemini-3-pro-image. Their preview identifiers were scheduled to shut down on June 25.

Use exact identifiers in configuration

A display name such as Nano Banana Pro helps a person choose a family. An API request needs the exact supported identifier. Keep the two concepts separate in your application and show the request ID in technical documentation.

When moving to a stable identifier, update environment configuration, saved presets, automated examples, and any model allowlist. Check each environment independently; staging and production can drift.

Compare the jobs, then choose defaults

Do not assign one default merely because it is labeled Pro or Flash. Review representative generation and editing tasks against the quality standard and budget for each job. Record which option the team selected and why.

Keep your acceptance set small enough to repeat after future updates. A reproducible comparison is more useful than a large unstructured folder of attractive images.

Finish the preview cleanup

This migration window is now historical. Search for remaining preview identifiers before copying older code. Current examples should point developers to the live catalog, where model access can be checked for their selected pricing group.