I have created around 5 promo codes for my in app product which is a one time purchase on Google Play console, and I want to redeem it through my app but I am not able to do that, as my app does not provide more options by which I can redeem it through, like the purchase dialogue comes to the screen and it only allows me to select the test card option for the purchases (as of now my app is in development stage), so my questions are:
Is I have to create/put some more code in my app to able to use promo code. Right now I am using react native IAP library to do so. If yes, than is there any specific link/document which I have to follow to implement the promo codes.
Can I redeem code outside my app, by putting it directly on play Store app (in redeem & gift card section) for in-app purchases (subscription and one time purchase). If yes, what all are the scenarios which I have to follow to validate the purchase, or whom can I give that redeem purchase through play store directly?
It is not a matter of code, I think. Probably you have set up your google store account as a license tester, which will only allow you to use test cards. If you want to test promo codes, you have to remove your email from the license testers list, which you can do in your developer account in google play console, in setup -> license testing (play console image).
Yes, the user can redeem promo codes outside your app, directly in the Play Store app. Go to you accounts -> payments and subscriptions -> Redeem promo code, or something like that (Only auto-generated one-use codes can be redeemed this way). Then, the code will be already redeemed for the user, so when he goes back to your app, when you call the purchase or subscribe method, with the right productId, the Google Play billing library should recognize the promo code is applied and there should be no charge.