What Happens to a Transaction If It Stays in the Mempool for Too Long without Being Confirmed?

If a transaction remains unconfirmed for an extended period, it may eventually be dropped from the Mempool of some or all nodes. This usually happens because nodes have limited memory and prioritize newer, higher-fee transactions.

The transaction can be re-broadcast later. Alternatively, the user can attempt to replace the transaction by submitting a new one with the same 'nonce' and a higher fee, a process called 'Replace-By-Fee' (RBF).