PokeIdle
PLAY FREE How to Redeem Codes in PokeIdle, Version by Version
The reviewed public pages do not document a redeem-code screen. A referral field serves a different purpose.
Version by version
Pokeidle.net: Save and Load are the account tools. There is no code entry. Pokeidle.io: the FAQ covers the account, Gems, and offline, and it does not cover a code. Pokeidle.com: sign-in, no code field on the public app shell. Poke Idle World: a referral query on the URL, not a typed promo code.
If a future patch adds a box, it will sit in that game's own menu and the codes table will gain a row with the reward and the date. Until then, a site that emails you a code is guessing.
Pokedle has the same search collision. Redeeming a puzzle code is a different product. Read PokeIdle versus Pokedle and the safety notes before you paste a script into the console.
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FAQ
Where is the code box on Pokeidle.io?
The public landing and FAQ do not include one.
Where is it on Pokeidle.net?
The shell shows Save and Load. It does not show a code field.
What about console scripts on Reddit?
They edit a save in the browser. They are not supported, and they can break the save. This site does not print them.