Here are the current gem codes I found for 99 Nights in the Forest :

Code Reward Notes
afterparty 15 gems/diamonds Redeem in the in-game Codes menu
yay fishing 2 gems/diamonds Type this in chat while actively fishing
To redeem them, open the game’s **Diamonds** menu, tap **Codes** , then enter the code and submit it. The **yay fishing** one is special because it only works in-game while you are fishing, not in the lobby.

A few things to know:

  • These codes are one-time use per account.
  • Code availability can change fast, so some lists may go stale.
  • An older code, happyhalloween , is listed as expired.

Current active gems

If you only want the working gem codes right now, use:

  1. afterparty
  2. yay fishing

TL;DR

The active gem codes currently reported are afterparty for 15 gems and yay fishing for 2 gems, with the second one requiring you to be fishing in-game when you type it.