What should a custom 404 error page include?

A well-designed 404 page should include your site's branding (logo, navigation, footer), a clear human-readable message explaining the page wasn't found, a search bar for self-recovery, links to popular or related content, a link to the homepage, and optionally a 'report broken link' mechanism. Always return an actual 404 HTTP status code — never a 200.

How do I set up custom error pages in Nginx?

Use the error_page directive in your server block: 'error_page 404 /errors/404.html;' then create a location block for /errors/ with the 'internal' directive to prevent direct access. For dynamic error pages, use a named location with proxy_pass to forward to your application backend, passing X-Original-URI so the app knows which URL failed.

Why shouldn't I redirect all 404 errors to the homepage?

Redirecting all 404s to the homepage creates a poor user experience because users lose context about what they were looking for. It also sends incorrect signals to search engines — Google may interpret it as your homepage being the canonical for every missing URL, and it prevents you from identifying and fixing broken links through analytics data.

How do I track analytics on error pages without inflating pageview counts?

Track error pages as custom events rather than pageviews. In Google Analytics 4, use gtag('event', 'error_page_view', {...}) with parameters like error_code, requested_url, and referrer. Also track recovery actions (search submissions, suggested link clicks) as separate events to measure which recovery mechanisms are most effective.

What is the difference between handling errors in Express middleware vs Spring Boot ErrorController?

In Express, 404s are caught by a middleware function registered after all routes (a standard middleware with req, res, next), while 5xx errors use a four-argument error-handling middleware (err, req, res, next). In Spring Boot, you implement the ErrorController interface with a single @RequestMapping('/error') method that reads the status code from HttpServletRequest attributes and returns different view templates based on the code.

Implementing Proper Error Pages for UX