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URL Contains Underscores

Google treats underscores as word-joiners — "best_running_shoes" is read as "bestrunningshoes".

notice Impact: low URL_HAS_UNDERSCORES 2 min read Updated

Why it matters

Google treats underscores as word-joiners — "best_running_shoes" is read as "bestrunningshoes". Hyphens are always the safer choice for word separation.

Address when convenient — notices usually mark a polish opportunity rather than a defect. Estimated SEO impact: low — small marginal improvement, but cheap to fix.

How to fix

  • Replace underscores with hyphens in URLs
  • Set up 301 redirects from old underscore URLs to the new
  • Update internal links to the new URLs

Common causes

If the rule is firing across many pages, the root cause is almost always one of these:

  • Templating engine emits an empty value when the page-level metadata field is null.
  • New pages inherit a placeholder ("Untitled", "Lorem ipsum") that was never replaced before publish.
  • CMS plugin overrides the metadata field after the theme sets it, with the plugin value missing.
  • Server-side rendering and client-side hydration disagree, leaving the wrong value in the static HTML.

Anti-patterns to avoid

Even with the best intentions, these "fixes" make the issue worse — recognise them so you don't ship them:

  • Copy-pasting the same title/description across templated pages.
  • Leaving raw template syntax ({{title}}) in the production HTML.
  • Letting auto-generated metadata override hand-written values.

How atlookup detects this

Our crawler renders each page with a real headless browser, then parses the document <head> and URL shape, applying the M8.T terminology audit rules. Pages where the rule fires for url contains underscores are flagged on the report.

If you'd like to see this rule fire on your own site, run a free 60-second audit — every page is reported with the exact lines that triggered it.

Tools to verify the fix

Once you've applied the fix, double-check with these external validators:

  • Google Search Console — Confirms how Google currently sees your title/description in SERPs.
  • Lighthouse — Catches missing or duplicate metadata across pages.

Frequently asked questions

Why does URL Contains Underscores matter for SEO?

Google treats underscores as word-joiners — "best_running_shoes" is read as "bestrunningshoes". Hyphens are always the safer choice for word separation.

How do I fix url contains underscores?

Replace underscores with hyphens in URLs Set up 301 redirects from old underscore URLs to the new Update internal links to the new URLs

Is this a critical SEO issue?

Address when convenient — notices usually mark a polish opportunity rather than a defect. Estimated SEO impact: low — small marginal improvement, but cheap to fix.

How does atlookup detect url contains underscores?

Our crawler renders each page with a real headless browser, then parses the document <code>&lt;head&gt;</code> and URL shape, applying the M8.T terminology audit rules. Pages where the rule fires for url contains underscores are flagged on the report.

How long does it take to fix?

5–15 minutes per page. Most teams batch similar issues across templates so the per-page time goes down at scale.

TITLE_MISSING

Missing Page Title

The <title> tag is the single most important on-page SEO signal — Google uses it as the clickable headline in search results.

META_DESC_HAS_PLACEHOLDER

Placeholder Text in Meta Description

Phrases like "Lorem ipsum" or "Your description here" in meta descriptions signal an unfinished page — this kills SERP credibility.

TITLE_HAS_PLACEHOLDER

Placeholder Text in Page Title

Placeholder text like "Lorem ipsum", "Untitled", or "Page Title Here" signals the page was never finalized — this destroys SERP credibility and CTR.

META_DESC_MISSING

Missing Meta Description

Without a meta description, Google generates a snippet from page content — sometimes scraping boilerplate or navigation.