What are the best practices for security in Next.js applications?

Thank you for posing such a critical question, especially in today's landscape where web security cannot be overstated. As a Full Stack Developer with a strong inclination toward the front-end spectrum, particularly with Next.js, I've prioritized security in every application I've built. Next.js, being a powerful React framework, offers a lot of built-in features that, when leveraged correctly, can significantly enhance the security of web applications. First and foremost, Content Security Policy (CSP) is a security standard that I always ensure to implement. CSP helps in preventing Cross-Site Scripting (XSS) attacks by specifying trusted sources for content like scripts, images, and styles. In Next.js, this can be achieved through the creation of a custom _document.js file and setting the CSP headers using the setHeader method in Next.js API routes or by configuring your server to include these headers in responses...