Hiring an Amplify.js developer can greatly enhance your web application's performance. Amplify.js is a powerful library used for managing AJAX requests, client-side browser storage, and application messaging. A skilled Amplify.js developer can help you create a more robust, efficient, and interactive web application. They can simplify the process of handling AJAX calls, storing data, and publishing-subscribing messages in your application. This can result in a faster, smoother, and more user-friendly interface that can ultimately drive user engagement and satisfaction.