Credit card spending uses two buckets
When you buy something with a credit card, two things can happen at the same time. The spending category goes down because you used money from that envelope. If the category had enough money, ReadyCents also reserves that same amount in the card payment category.
Example: Groceries has $300 available and you spend $50 on a credit card. Groceries drops to $250, and the card payment category gains $50. That means the money is still in your bank account, but it is now reserved for paying the card.
Unfunded credit spending creates debt
If the envelope does not have enough money, ReadyCents does not pretend you have payment money. The spending envelope becomes overdrawn and the card balance grows. You can patch the envelope later by budgeting money or moving money from another envelope.
This is the behavior that matters: funded credit spending creates payment money. Unfunded credit spending creates debt.
Credit card payments are transfers
A card payment moves money from a checking or savings account to the credit card account. It lowers the bank account balance and lowers the card balance. It should not count as a new expense because the expense already happened when you made the purchase.
The payment itself is a transfer row, not a normal spending-category transaction. ReadyCents derives the linked payment envelope's activity automatically so the budget can show how much reserved cash the payment used.