Want to improve your search engine optimization (SEO) and inch higher up the search engine results pages? While content quality and backlinks play a significant role, you may be overlooking the hidden importance of crawlability.
Crawlability problems make it harder for Google to assess your site, slowing down or even preventing you from achieving the rankings you deserve. Read on to discover the most common issues and how to prevent them from sabotaging your SEO.
In this article, I’ll walk you through:
- What crawlability problems are,
- How crawl issues impact SEO, and
- The 11 most common crawling problems.
Plus, I’ll walk you through how to fix them.
What Are Crawlability Problems?
A crawlability problem is anything that prevents Googlebot from finding new pages or moving swiftly across your entire site. One common issue is blocked URLs in your robots.txt file, which prevents bots from accessing specific pages. Another is the noindex tag, which tells search engines not to index specific pages. However, there are many more potential mistakes to avoid.
Think of search engine indexes as libraries. When you enter a query, it’s like asking the librarian for a book recommendation. However, just like an actual librarian, Google can’t recommend information it doesn’t know about.
While web admins could simply submit their sites to search engines, this would lead to indexes that miss much of the internet. That’s why Google takes a more active, automated approach, directing Googlebot and its friends to crawl the internet. Other major search engines use similar methods.
Googlebot automatically finds new pages not listed in Google’s index, but it also helps the search engine keep track of content updates and site architecture changes that affect pages it already knows about. It does this by following internal links across each page on a site and outbound links that lead to other sites.
How Do Crawlability Problems Impact SEO?
The worst ways crawlability problems may affect SEO include:
- Incomplete indexing. Whether it’s due to broken links, errant noindex tags, or incorrectly blocked URL pathways in your robots.txt file, incomplete indexing has one outcome: Unindexed pages never appear in search. This is the SEO equivalent of hoping something will grow out of a garden without seeds.
- Dropped pages. Search engines tolerate occasional server downtime and errors. However, if 404 or 5xx errors happen too frequently, Google may drop affected pages from its index. The worst outcome is for high-ranking pages to suddenly lose their search positions and all the traffic they’re generating as a result.
- Delayed SEO feedback. SEO is a constant process, but you can’t assess how page or site changes affect your rankings until search engines recrawl everything. Poor crawlability drags this process out longer, making it more difficult to make time-sensitive optimizations.
Given how important crawling is to Google’s index, anything that impacts the process can negatively affect SEO. In fact, some crawlability mistakes are so damaging that they might prevent new pages from ever ranking or even cause Google to drop your highest-ranking content from the index, destroying all your hard work!
How Crawlability Problems Affect AI Search Visibility
AI Overviews, ChatGPT, Perplexity, and every other answer engine you’re trying to get cited by depend on the same first step Google does. A bot has to reach your page before anything on it can be quoted, summarized, or linked. Google’s AI Overviews still draw primarily on Google’s own index, so the crawlability work you do for traditional search carries over directly. But platforms like OpenAI and Perplexity send their own crawlers, including GPTBot and PerplexityBot, and a robots.txt block, a noindex tag, or a page that times out keeps those bots out just as effectively as it keeps Googlebot out.
That means a crawlability audit that only checks for Googlebot is checking half the problem. Review your robots.txt file and server logs for AI-specific user agents the same way you would for Googlebot, and don’t assume a page performing well in Google search is automatically visible to AI systems. Each one crawls, renders, and indexes independently.
How To Test Your Site for Crawlability Issues
Before you can fix a crawlability problem, you have to find it, and that starts with seeing your site the way a bot does, since a browser renders it very differently for you. Run a full crawl with a tool like Screaming Frog’s SEO Spider or a site audit platform such as Ahrefs or Semrush, starting from your homepage the same way Googlebot would. Compare what the crawl turns up against your Google Search Console Coverage report. Search Console shows what Google has indexed, while a third-party crawl shows everything technically reachable, and the gap between the two usually points straight at a crawlability problem. Re-crawl after each fix to confirm it worked before moving to the next issue.
11 Common Crawlability Issues and How To Address Them
Crawlability problems take many forms, but these 11 are some of the most common and damaging, so it’s crucial you understand how to fix each.
1. URLs Blocked by Robots.txt
Located in the root directory of your website, the robots.txt file provides instructions for various bots, including those used by search engines, advertising services, and performance optimization services. These instructions allow you to limit the pages specific bots can access. You can also block entire URL pathways.
A robots.txt disallow is guidance, not a hard block, though. It’s a strong signal that keeps well-behaved bots away, but it won’t stop a page from being indexed if enough other sites link to it. If you need a page fully excluded from search results, pair it with a noindex tag instead (more on that next), and see our robots.txt syntax guide for the exact directives to use.
Naturally, if your robots.txt blocks URLs you didn’t intend to block, search engines may have trouble indexing your site. Fortunately, you can detect potential issues in a few ways through Google Search Console. How to spot it:
- Checking the list of Search Console indexing errors on the Pages tab under Indexing.
- Checking robots.txt validity in the settings section.
- Entering any URL into the URL inspect bar at the top.
Other search engines, such as Bing, offer similar tools. Third-party software like Screaming Frog’s SEO Spider also lets you check for robots.txt errors affecting many kinds of bots.
How to fix it: When you find issues, delete the mistaken URLs manually, just like editing any other text file, or use a robots.txt generator to create a new file that works as intended. And don’t stop at Googlebot. If showing up in ChatGPT, Claude, or Perplexity results matters to you, check that your robots.txt isn’t blanket-blocking AI crawlers like GPTBot, ClaudeBot, or PerplexityBot without a strategic reason to keep
2. Noindex Tags
Although you can prevent crawl bots from reaching specific pages with robots.txt rules, search engines may still find and index these pages through other means. However, the noindex tag in the HTML head tells them not to index the page, regardless. This is great when you don’t want non-canonical or admin content indexed, but the tag occasionally ends up on pages that shouldn’t have it.
Luckily, you can find mistaken noindex tags in several ways.
How to spot it:
- Entering URLs in Google Search Console or Bing Webmaster Tools.
- Entering a directive in Screaming Frog’s SEO Spider to find all noindex pages.
- Conducting a site audit through certain SEO tools.
- Using a browser extension to check for noindex tags while debugging other issues.
If you encounter many pages with unintended noindex tags, a plugin or automated tool is usually to blame, so it’s worth checking any you’re using. You can fix the issue by removing the noindex tags from individual page publishing settings or altering settings in the third-party tools you’re using.
3. Redirect Chains
Redirects are useful for sending traffic to a different page, temporarily or permanently, such as when a site changes domains or a product gets discontinued and you want to point visitors to a category page instead.
The trouble starts when a page redirects to another page that also redirects. That’s a redirect chain, and it slows load times for visitors while burning through the limited crawl budget search engines give your site. Google typically abandons a crawl after about five redirects to conserve resources. Don’t treat that as your target, though. Victorious’s own technical standard caps redirect chains at two to three hops, well inside what any search engine tolerates, and it keeps pages loading fast for visitors too.
How to spot it: Check individual URLs in Search Console, or run a full site audit through a tool like Ahrefs or Semrush to catch chains across your whole site at once.
How to fix it: Consolidate any redirect chain you find into a single, direct redirect using your site’s usual method for handling redirects (typically .htaccess, nginx.conf, or a plugin).
4. 404 Errors
A 404 error indicates that a page wasn’t found, which could occur due to deletion, a URL error, or the content being moved without a redirect. Whatever the cause, it’s bad news for SEO because crawl bots can’t find and index the content either, and bots that follow broken links may get stuck without a way to reach other pages across your site that need index updates.
How to spot it: Like other page-level crawling problems, you can detect 404 errors when checking individual URLs in Search Console, and you may also find several under the Pages tab. However, site audits offer the best way to scan your whole site in its current state.
How to fix it: You’ll need to address the cause by:
- Redirecting deleted or moved content.
- Fixing URL typos.
- Contacting other sites to correct backlinks.
You can also create custom 404 pages that act as catch-all solutions to help users navigate elsewhere when they reach your site through a bad link.
5. JavaScript Rendering Issues
Search engines and AI crawlers alike read your page the way it comes back from the server first. If the content that matters — your text, your headings, your internal links — only appears after JavaScript runs, some bots never see it at all. Our crawl analysis puts a number on the cost. Google requires roughly nine times more time to crawl a JavaScript-heavy page than a plain HTML one. That’s crawl budget spent on rendering instead of discovering your other pages, and pages that depend on client-side JavaScript for their core content or internal links are the ones most likely to fall behind on indexing.
How to spot it: Compare your page’s raw HTML (view source, before any script runs) against its fully rendered version in Chrome DevTools or Search Console’s URL Inspection tool. If your main content, headings, or internal links are missing from the raw HTML and only appear after rendering, that content is at risk of being missed or delayed. AI crawlers like GPTBot and PerplexityBot render JavaScript even less reliably than Googlebot does, so content locked behind client-side scripts is often invisible to answer engines even when Google eventually indexes it.
How to fix it: Serve critical content, especially headings, body copy, and internal links, in the initial HTML. Injecting it with JavaScript after the page loads risks bots missing it. Server-side rendering, static rendering, or a rehydration approach all keep that content visible to bots that don’t fully execute scripts. See our full guide to JavaScript SEO for the specific rendering approaches and their tradeoffs.
One Victorious client, Lonestar Challenge Coins, had JavaScript rendering errors blocking its homepage from being indexed at all. Fixing that, alongside cleaning up keyword cannibalization and launching new landing pages, was part of a strategy that contributed to a 142% increase in organic conversions.
6. Slow Page Load Speed
Search engine bots allocate limited amounts of crawl time to each website, as well as limited page budgets per session. When pages load slowly, this cuts into your site’s crawl budget, and the bot may leave well before it reaches your page limit, drastically slowing down the indexing of recent site updates. Crawl budget management is its own discipline worth understanding beyond this one cause. See our guide to crawl budget optimization for the full picture of what influences it and how to protect it.
How to spot it: Check page load time using tools like PageSpeed Insights and Lighthouse. PageSpeed Insights offers several recommendations to improve specific issues.
How to fix it: Some general things you can do to speed up any site include:
- Minifying CSS and JavaScript files.
- Enabling browser caching.
- Optimizing images.
- Using a CDN.
- Using lazy loading.
- Using asynchronous CSS and JavaScript loading.
Of course, different things slow down crawl bots compared to humans browsing your site, so consider the following, too:
- Optimizing site architecture and interlinking
- Submitting sitemaps to search engines
- Using robots.txt to optimize crawling and noindex tags to block access to irrelevant pages
One more factor affects both crawl efficiency and load speed. Google indexes the mobile version of your site by default, not desktop. If your mobile pages are slower or missing content that’s present on desktop, that’s what Google is crawling and ranking against, so run your speed checks on mobile first.
7. Duplicate Content
Content that’s identical or incredibly similar can confuse search engine bots, as they may not know which version of a page to index. One common example of this is when ecommerce sites use URL parameters for color or size variations of the same product. Another occurs with archive, tag, or category pages used by content management systems such as WordPress.
URL parameters deserve their own look, not just a passing mention. Audit your site for session IDs and tracking parameters, since each one can generate what looks like a brand-new page to a crawler even though the content is identical. Not every parameter is a problem, though. A parameter like ?color=black might be worth letting Google crawl, since people search by color or size, while a parameter like ?sort=rating rarely needs its own indexed URL. Google retired its old URL Parameters tool in 2022 and now handles most of this automatically, so your main lever is a canonical tag pointing parameterized URLs back to the clean version, with a robots.txt disallow rule for parameter patterns you never want crawled at all.
How to spot it: Look for duplicate title tags and near-identical content in your site audit tool, or search Google for an exact phrase from your page in quotes to see how many of your own URLs come up.
How to fix it: To fix duplicate content issues that result from URL variations, add canonical links to the head section of the HTML to tell search engines which URL to index. Other things to do include:
- Blocking access to printer-friendly versions of pages through robots.txt.
- Adding noindex tags to archives, tags, and categories.
- Setting up 301 redirects to consolidate pages with and without the www prefix or to redirect HTTP pages to the HTTPS version.
- Using internal links that point to preferred page versions only.
8. Bad Site Architecture
Bad site architecture impacts navigation both for humans and crawl bots. To improve the user experience and eliminate crawling problems, follow these rules:
How to fix it: To improve the user experience and eliminate crawling problems, follow these rules:
- Ensure all important content is accessible within three clicks of the homepage.
- Follow a strategic linking strategy to avoid orphan pages (pages with no internal links pointing to them at all) and direct the flow of traffic and crawl bots where you want.
- Avoid using too many deeply nested subcategories.
- Use consistent navigation menus.
- Fix broken links.
- Use breadcrumb navigation and structured data.
Even if you’re already doing all of this, you should still check for crawl issues in Search Console and run occasional SEO site audits, as this can help you spot anything you’ve missed.
9. 5xx Errors
A 5xx error indicates that your server couldn’t fulfill a user’s request. For crawl bots, this prevents them from crawling or indexing the affected page.
How to spot it: Check Search Console’s Pages report for 5xx errors, or run a site audit to catch them across your whole site.
Here are some typical 5xx errors:
- 500 Errors: These are generic server errors. They usually indicate issues with code or permissions, so check server-side scripts, configuration files, and memory limits.
- 501 Not Implemented: This error occurs when your server can’t complete the type of request a browser makes. You might need to update the server software.
- 502 Bad Gateway: This error occurs when other servers between yours and the visitor don’t function correctly. An overloaded CDN is a common cause of 502 errors.
- 503 Service Unavailable: This error indicates overloading or temporary maintenance outages. You might need to upgrade your server capacity if it happens frequently.
- 504 Gateway Timeout: This error indicates slow responses from upstream servers. Check CDNs and other services for issues.
- 505 HTTP Version Not Supported: This error typically happens when your server software is outdated, so check that everything is current.
10. Access Restrictions
Sometimes a page is technically crawlable in every way described above, but still walled off by IP restrictions, a firewall rule, or a login requirement that blocks bots along with unauthorized visitors. That’s a legitimate choice when you’re intentionally restricting access to gated content, staging environments, or member-only pages. It becomes a crawlability problem only when it happens to pages you actually want indexed.
How to spot it: Check server and firewall logs for blocked requests from Googlebot’s user agent and IP ranges, and use Search Console’s URL Inspection tool to see whether Google can fetch a given page. A page that returns a login wall or an access-denied response to Googlebot the same way it would to a blocked visitor won’t get crawled, no matter how clean the rest of your technical SEO is.
How to fix it: Remove authentication requirements from any page you want indexed, and update firewall or IP-blocking rules to let verified search engine bots through. If certain content needs to stay restricted, that’s a legitimate choice. Don’t expect Google to index what it can’t get past the login screen.
11. Internal Broken Links
Internal broken links occur when the internal links on a page direct users or bots to deleted or moved content.
How to spot it: The best way to find these links is to perform regular site audits (especially after changing the URLs of any content).
How to fix it: If you do find internal broken links, there are two simple ways to fix them:
- Adjust the link to the page’s new URL.
- Redirect the old URL to the new URL.
Option one is quick and convenient enough for one link, but you’ll probably want to use a redirect if you need to adjust several. Another alternative when using a CMS like WordPress is to employ an internal linking plugin for site architecture management. That way, you can simply adjust the URL in the plugin to change all old links at once.
Catch Crawlability Issues With a Comprehensive SEO Audit
Don’t let crawling errors keep your site from ranking. Take advantage of our comprehensive site audits and technical SEO services to monitor broken links, site structure, and overall performance.
We’ve seen firsthand how much traffic a hidden technical fault can cost. A comprehensive audit for GoFundMe uncovered a subdomain that indexing issues had made completely invisible to search engines, and fixing it brought in more than 58,000 unique visits that had nowhere to go before.
When your website functions like a well-oiled machine, visitors will keep returning, giving you the engagement and credibility needed for long-term growth. Schedule a free consultation today and learn more about how our SEO and web maintenance services can keep your site in tip-top shape.
