FaucetPay merchant callbacks and the retry schedule
The token is single use and they retry at fixed intervals, so check your own order first and answer 200 before verifying again.
Tagged “callbacks”
3 entries
Create a NOWPayments invoice and handle the callback
An API key on the way out, a signed and key-sorted JSON payload on the way back. The sorting requirement is the part that trips people.
Credit a deposit exactly once, however many callbacks arrive
A unique index on your own reference turns duplicate callbacks, browser refreshes and manual replays into no-ops instead of free balance.