G29 — Chapter 7 - Technical SEO

Criterion G29 : Avoided Soft 404s — guide + checklist

PART 1 - Fundamentals Chapter 7 - Technical SEO Keyword : soft 404 évités

This criterion seems “simple”, but it creates many discrepancies in production.

The **G29 — Avoided Soft 404s** criterion is part of our SEO checklist (335 criteria). Here, you have a **practical** method to check and fix it — with a concrete example.

What exactly this criterion covers

This criterion seems “simple”, but it creates many discrepancies in production.

**G29 — Avoided Soft 404s** (Chapter 7 - Technical SEO): Empty/error pages must return true 404, not 200

Why it matters (SEO + UX)

Why it matters: it is a lever for CTR and perception in SERP. When poorly applied, we often observe: ambiguity (wrong associated query), duplication between pages, or loss of performance on impressions.

On volume-generated sites, this criterion also acts as a **safeguard**: a stable rule prevents 1,000 errors at once.

How to check (step by step)

Approach: check by crawl (list + export). Recommended tool: **WebPageTest**.

  1. Open the page in Chrome → DevTools → Performance/Network tab.
  2. Run PageSpeed Insights and note the main weak point.
  3. Check if the problem repeats on “money” pages.

Tip: first isolate 10 “representative” URLs (top pages + generated pages) before scaling the fix.

How to fix properly

Strategy: fix the minimum necessary, then stabilize.

  • Fix the biggest cost source (images, JS, fonts, cache).
  • Retest, then apply to the template (not page by page).
  • Add a safeguard: weight budget (KB) and CI check if possible.

Then: re-crawl 50–200 URLs, then monitor Search Console for 7–14 days (impressions/CTR/indexing).

Concrete example (illustrative)

Example (illustrative):

  • **Context**: training page for dentist in Nice
  • **Before**: Lighthouse: 44/100 (heavy JS, unoptimized images).
  • **After**: Lighthouse: 78/100 (lazy-load, compression, cache).
  • **Note**: Goal: stabilize LCP.

Checklist to tick

  • [ ] Measure before/after
  • [ ] Respects: empty pages
  • [ ] Improvement on template
  • [ ] No CWV regression
  • [ ] Cache and compression OK
FAQ

Frequently asked questions — G29

What is the most common error on “Avoided Soft 404s”?

Trying to “optimize” by adding too many keywords, which degrades readability and creates repetitions.

What is the fastest tool to check at scale?

For this type of criterion, a crawl (e.g., Screaming Frog) + targeted verification in WebPageTest is generally the fastest combo.

How to prevent this from happening on 10K generated pages?

Freeze an auto-generation rule (title/structure/schema/URLs) + add automatic control (crawl or test) before production import.

Ready to go from theory to action?

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