Search Atlas Help Center

🔗 Fix Unwanted URL Parameters in Canonical Links

Open in
View as Markdown Open in ChatGPT Open in Claude
Camilo Aponte

Camilo Aponte

Last updated on Sep 30, 2026

🧭 Overview

When you run a Screaming Frog crawl on a site managed with Search Atlas, you may notice canonical links containing an extra URL parameter: is_otto_page_fetch=1. This parameter is appended by Otto, the Search Atlas automation engine, during page fetches for analysis. It is an internal crawl signal and should never appear in your canonical tags on the live site. If it does, search engines may index the wrong canonical URL, which can negatively affect your SEO.

This article explains why this happens, how to verify the issue, and the exact steps to resolve it inside Search Atlas and Screaming Frog.

🔍 Why This Parameter Appears

Otto adds is_otto_page_fetch=1 to page requests so it can identify its own crawl traffic internally. Under normal circumstances this parameter exists only in the HTTP request and is never written to the page's HTML. However, if your site or CMS dynamically generates canonical tags based on the current request URL, the parameter can be captured and rendered inside the <link rel="canonical"> tag. This is a site-side configuration issue that Search Atlas tooling can help you detect and fix.

✅ Step 1 — Confirm the Issue in Screaming Frog

  1. Open Screaming Frog and crawl your site.
  2. Click the Canonicals tab in the lower panel.
  3. In the filter dropdown, select Contains a Canonical URL.
  4. Export the list and search for any canonical value containing is_otto_page_fetch=1.
  5. Note the affected URLs. If only a handful appear, the issue is likely isolated to pages with dynamic canonical logic. If the parameter is widespread, your CMS is globally reflecting request parameters into canonical tags.

⚙️ Step 2 — Configure Parameter Filtering in Search Atlas

Search Atlas lets you define URL parameters that should be stripped before canonical evaluation. Follow these steps:

  1. Log in to Search Atlas and navigate to your project.
  2. Open Settings and select Crawl Configuration.
  3. Scroll to the URL Parameter Exclusions section.
  4. Click Add Parameter and enter is_otto_page_fetch (without the value).
  5. Save your settings. Otto will now strip this parameter from all URLs before they are evaluated, reported, or compared against canonical values.

After saving, re-run your site audit from within Search Atlas. The parameter should no longer appear in canonical link reports generated by the platform.

🛠️ Step 3 — Fix the Canonical Tag on Your Site

Even after adjusting Search Atlas settings, you must prevent your site from writing the parameter into the canonical tag in the first place. The correct fix depends on your CMS or framework:

  • WordPress (Yoast / Rank Math / All in One SEO): These plugins build canonical URLs from get_permalink() rather than the raw request URL, so they are usually not affected. If you are using a custom canonical filter or a theme function that reads $_SERVER['REQUEST_URI'], update it to use get_permalink() or home_url(add_query_arg(array(), false)) with query args explicitly stripped.
  • Custom CMS / server-side rendering: Locate where the canonical meta tag is built and ensure the URL is constructed from the canonical page path, not the live request URL. Strip all query parameters before inserting the value into the tag, or maintain an explicit allowlist of parameters that are permitted in canonicals.
  • Cloudflare / CDN or edge workers: If a worker or transform rule is injecting or reflecting parameters, add a rule to strip is_otto_page_fetch before the canonical tag is generated or cached.

📋 Step 4 — Re-Crawl and Verify in Screaming Frog

  1. After updating your site, clear any full-page cache (WordPress cache plugins, Varnish, Cloudflare cache, etc.).
  2. Return to Screaming Frog and run a fresh crawl.
  3. Go back to the Canonicals tab and re-export the list.
  4. Confirm that no canonical URLs contain is_otto_page_fetch=1.
  5. If affected pages had previously been indexed with the incorrect canonical, submit them via Google Search Console under URL Inspection > Request Indexing to prompt Google to re-evaluate the correct canonical.

🚫 Common Mistakes to Avoid

  • Only fixing it in Screaming Frog settings: Configuring Screaming Frog to ignore the parameter hides it from reports but does not fix it on your live pages. Always fix the source.
  • Caching old pages: If your CDN or server cache is serving stale HTML, the bad canonical will persist even after a code fix. Always purge caches after making changes.
  • Blocking Otto entirely: Blocking the Otto crawler user agent in robots.txt will prevent Search Atlas from auditing your site. Instead, use the parameter exclusion settings described in Step 2.

💬 Need More Help?

If you need further assistance, open the chat widget in the bottom-right corner of the platform and type human teammate to be connected with a member of our team.