Batch processing (or Bulk processing) in a payment gateway means collecting a bunch of payment transactions throughout the day and then processing them all at once at a specific time. Instead of handling each transaction individually in real-time. First the business collects all the payments from multiple transactions and groups them together into a “batch.” It is then sent to the payment processor in one go. Once done, the results are sent back to the business showing which transactions were successful and which weren't.