A system and method for obtaining user approval for transactions. The system includes an authorization system that is communicably coupled to one or more transaction computer systems that execute at least some transactions that require user approval. When a transaction system is seeking to execute a transaction that requires user approval, the transaction system sends a user approval request to the authorization system. The authorization system then retrieves the user's communication preference from a database and transmits an affirmatively actionable message to the user according to the retrieved communication preference. The messages can include an email with an approval link to click or a text message that the can be replied to. When the authorization system receives confirmation from the user that the user approves the request, the authorization system then transmits approval for the transaction to the appropriate transaction system, which then proceeds to execute the transaction.