Designing a website without 404s

Original Article ↗ Hacker News Discussion ↗

Concept: Fuzzy URL Matching Instead of 404s

  • Site maps mistyped or non-existent product URLs to the “closest” supplement page instead of returning 404.
  • Originally motivated by auto-migrating changing URL schemas and product renames.

Perceived Benefits

  • Can be helpful on search-centric sites: users already expect to browse results, not hit precise slugs.
  • Useful for typo recovery and link migrations.
  • Multiple URLs pointing to the same content is seen as acceptable by some, especially when an ID in the path is the true key.
  • Some users frequently “edit the URL bar” (e.g., for ticket IDs, product codes) and appreciate when that works.

Main Usability and Safety Concerns

  • 404 exists to clearly signal “this doesn’t exist”; silent redirection can mislead users into thinking they got the right page.
  • For medications/supplements this is considered potentially dangerous: a near match could be the wrong product yet look “correct enough.”
  • Bookmarks and shared links might later resolve to different content if matching changes over time.
  • Troll URLs with offensive or conspiratorial text can resolve to innocent products, creating reputational issues.

SEO and Web-Architecture Concerns

  • Risk of duplicate-content and indexing confusion when many URLs resolve to the same page.
  • Debate over whether Google penalizes this; some cite guidelines and migrations that worked fine with proper 301s and canonicals, others see it as fragile and opaque.
  • URLs are treated as a public API surface; fuzzy matching effectively commits the site to an unbounded set of “supported” URLs.
  • Archiving and link-rot handling become harder when URLs are non-deterministic.

Implementation and Scaling Issues

  • Similarity lookups on every bad URL can be expensive; suggestions to cache, throttle, and deprioritize in the database.
  • Large sites with millions of URLs may find fuzzy DB queries impractical.

Suggested Alternatives and Compromises

  • Keep proper 404 (or 410) status codes and show a rich “Did you mean…?” page with search, suggestions, and top similar URLs.
  • Use canonical URLs with IDs, and redirect only when ID matches but slug doesn’t.
  • For migrations, store old URLs and do explicit 301/302/307/308 redirects; use fuzzy matching only as on-page suggestions, with similarity thresholds.

Author’s Updated Plan

  • Track which URLs map to which products.
  • On 404:
    • If URL was previously associated with a product, redirect to that product.
    • If it’s a new, unknown URL, return a 404 page that lists similar products instead of silently redirecting.