Design verification and validation are the procedure to check during medical device development process that the product meets the specific requirements and error free. Design verification is testing that the design output meets the design input and requirements you have written. “Did you build what I said?” Design validation is intended to test how well you addressed the customer needs that caused you to write those requirements “Did you build a right thing?” I believe the right time to do design verification is at the end of each life cycle phase to be correct, complete, and consistent results. When the device reaches at this stage where its hardware or software prototype is fully functional; FDA requires medical device manufacturers to perform design verification and design validation processes to ensure that the finished product is safe and effective for its intended purpose.