The Balance endpoint gives access to balance information
The balance that you can use. However The accessible balance can easily change when the pending_debits settle. That's why total available is the balance that is "safe to spend".
Total balance of debit transactions that have not yet settled
Total balance of credit transactions that have not yet settled
Total balance of scheduled debit transactions
Total balance of settled transactions
Total balance in the lockbox
Total balance that is safe to spend. total_available = accessible - pending_debits - scheduled_debits