RewardTracker.io never asks for a card number.
No. There is no bank login. Your bank stays out of it.
Two cards are free. A one-time $10 unlock adds the rest of the 48-card catalog on that account. There is no subscription.
The catalog is 48 US travel cards.
Only used credits count toward the fee. Pending stays off until you mark it used. Skipped does not count.