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Get Started Free →Use when reviewing templates, rendered HTML, or shared components related to Create a custom 404 error page. Validate the final browser-facing markup, not just the source framework abstraction.
| Test case | Without → With | Effect | Δ tokens | Δ turns |
|---|---|---|---|---|
| case-16 | ✗→✓ | ▲ Improved | -3% | 0% |
| case-01 | ✓→✓ | = Same ✓ | 0% | 0% |
| case-02 | ✓→✓ | = Same ✓ | -3% | 0% |
| case-03 | ✓→✓ | = Same ✓ | -5% | 0% |
| case-04 | ✓→✓ | = Same ✓ | -5% | 0% |
A generic browser 404 page causes users to leave immediately—a well-designed custom page provides recovery paths and keeps users engaged with your site.
Verify that this website has a custom 404 error page with helpful navigation options. Confirm the route returns HTTP 404 and not a branded page with a 200 response.
Create a user-friendly 404 page with search functionality and links to important pages. Ensure the server or framework returns status code 404 so the page does not become a soft 404.
Explain how custom 404 pages help retain users who encounter broken links and why returning 200 for missing pages creates soft-404 indexing problems.
Review templates, server-rendered HTML, and shared components that output markup related to Create a custom 404 error page. Flag exact elements, attributes, and routes where the rendered HTML violates the rule.
For full implementation details, code examples, and framework-specific guidance, see references/rule.md.
Rule page: https://frontendchecklist.io/en/rules/html/404-page
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