"The code is not valid"
Re-enter it slowly: Nintendo codes never contain hyphens, and a confused 0/O or 1/I is the usual culprit.
Redeem guide
Sixteen characters, one "Redeem Code" button — and a region that must match your Nintendo Account.

Quick answer
On your Nintendo Switch, open Nintendo eShop, choose your user, select Redeem Code on the left and enter the 16-character code, then Confirm. You can also redeem online at ec.nintendo.com/redeem while signed in to your Nintendo Account. The card must match the account's country.
Buy a Nintendo eShop Gift Card with cryptoFrom the HOME Menu, select Nintendo eShop (the console must be online) and pick the user whose Nintendo Account should get the funds.
It is in the menu on the left side of the eShop.
Type the code from your email. Nintendo eShop codes have no hyphens.
Select Confirm: the funds are added to the account balance and can be spent right away.
Handy when the console is not at hand — the balance syncs to it.
Sign in with the Nintendo Account linked to your console.
Type the 16-character code, select Next, check the amount and confirm.
Some cards and receipts carry two numbers. The download code is 16 characters without hyphens; the control number has hyphens and is not redeemable. Your GiftKong email contains only the download code.
Nintendo eShop cards are tied to a region: choose the one that matches the country set on your Nintendo Account.
Re-enter it slowly: Nintendo codes never contain hyphens, and a confused 0/O or 1/I is the usual culprit.
The card is for another country than your Nintendo Account (Settings on accounts.nintendo.com). Redeem it on an account from the card's region.
Check the account's balance history in the eShop — the funds may already be there. Each code works once.
Games, DLC and add-ons in Nintendo eShop, and Nintendo Switch Online memberships.
No — redeemed funds stay on the Nintendo Account until you spend them.
No. The card must match the country of the Nintendo Account; cross-region redemption is blocked.
Yes. GiftKong sells Nintendo eShop cards for the regions listed above, paid with Bitcoin, Ethereum, Monero, USDT and four other options. The 16-character code is emailed as soon as the payment confirms.
Yes — eShop funds belong to the Nintendo Account, so they are available on any Switch console where that account is used.
Nintendo eShop cards for your account's region, paid with crypto and emailed as soon as the payment confirms.
A real person reads every ticket and replies to the email on your order.
