Create a custom 404 error page
SkillWeb & browsingLets your agent review and validate the HTML markup of a custom 404 error page against front-end best practices.
Available today. Use it from your connected AI after setup.
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Then ask your AI: use the Create a custom 404 error page skill
About this capability
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.
What this skill tells your AI
The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/404-page/SKILL.md and read by ahel’s review.
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.
Quick Reference
- Custom 404 pages retain users who encounter broken or moved links
- Include search, navigation, and links to popular content
- Maintain consistent branding and site design
- Track 404 errors to identify and fix broken links
- Return a real HTTP 404 so the page is not treated as a soft 404
Check
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.
Fix
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
Explain how custom 404 pages help retain users who encounter broken links and why returning 200 for missing pages creates soft-404 indexing problems.
Code Review
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
Signals
- GitHub stars
- 74k
- Forks
- 7k
- Last commit
- Aug 2026
Advanced
- Catalog kind
- skill
- Gateway key
x-404-page- Source
- github.com/thedaviddias/front-end-checklist