Crawling a website's structure means automatically walking every page with a crawler and building a complete tree of its sections and URLs. A site crawler tool behaves like a search engine bot: it follows internal links, records each page, its response code, its nesting depth, and the relationships between sections. The output shows you the site the way Google sees it — with all its duplicates, broken links, and orphan pages.
This piece is part of our series on web scraping for SEO. Below we cover why you'd crawl a site's structure, what it reveals, and which tools do the job.
Why crawl your site structure
You can't check a site with hundreds of thousands of pages by hand. And structural problems are exactly what tend to hold back rankings: the bot burns its crawl budget on duplicates and junk URLs, important pages end up five levels deep and get indexed poorly, and internal links point to 404s. A structure crawl answers questions like:
- How many real pages the site has and how they're spread across sections.
- Which pages return errors (404, 5xx) and where redirects lead.
- Where duplicates have formed, by URL and by content.
- How deeply important sections are buried (nesting depth).
- How internal linking is arranged and whether there are orphan pages.
This data becomes the basis for a technical to-do list and helps you design a logical, flat structure that's convenient for both the user and the bot.
What a crawler collects
As it walks the site, for every URL the tool records the server response code, the address itself, the nesting depth, incoming and outgoing internal links, and the page metadata — title, description, and headings. In effect, crawling the structure and scraping title and header tags happen in a single pass: you get both the site tree and a table of metadata at once.
A particular strength of modern crawlers is building a visual tree. You can see the structure graphically, judge how pages are distributed across levels, and immediately spot anomalies: bloated sections, dead-end branches, and pages with no incoming links.
Site crawler tools: an overview
Desktop crawlers
Screaming Frog SEO Spider — the global standard. It scans a site by following internal links, collecting metadata, response codes, and link relationships, and builds out the structure. It can visualize the tree several ways (Crawl Tree Graph, Directory Tree, and more), execute JavaScript to crawl JS-heavy sites, and extract arbitrary data by XPath through Custom Extraction. There's a mode to compare two crawls — handy for tracking changes after fixes. The free tier covers up to 500 URLs, enough for small sites.
Sitebulb — a desktop crawler known for the clearest reports on the market. Beyond the crawl, it turns findings into prioritized, plain-English audit hints ("why this matters, how to fix it") and produces excellent structure and internal-link visualizations. A strong pick when you want the tool to interpret the data, not just dump it.
Netpeak Spider — a powerful desktop crawler with reports on the overview, site structure, and scraping. It exports the full URL-based structure, shows nesting depth, is flexibly configurable for the parameters you care about, and supports multiple proxies. Many SEOs praise its speed and comfort on large e-commerce sites.
Cloud / online crawlers
If you'd rather run a website crawler online — no desktop install, scheduled recrawls, shareable reports — the cloud audit tools are the answer:
- Ahrefs Site Audit and Semrush Site Audit — cloud site-audit crawlers bundled into their wider SEO suites, with health scores, issue tracking over time, and scheduled crawls.
- Lumar (formerly DeepCrawl), JetOctopus, and OnCrawl — enterprise-grade cloud crawlers built for very large sites and log-file analysis.
Checking what's actually indexed
To see which pages a search engine has really indexed (as opposed to what exists), cross-reference your crawl with Google Search Console (the Pages/Indexing report) and Bing Webmaster Tools. Screaming Frog and the cloud crawlers can pull the Search Console API directly into the crawl, so you can spot crawlable pages that aren't indexed — and indexed pages that shouldn't be.
Which one you pick comes down to scale and budget: for one-off audits and small sites the free tiers are plenty; for regular work on large projects, teams reach for Screaming Frog, Sitebulb, or a cloud crawler.
Crawling competitor sites
You can point a crawler not only at your own site but at a competitor's — for example, to export the structure of a large catalog or online store. Using XPath queries (say, against the breadcrumb structured data / schema markup), you can rebuild their category tree, which helps you design your own structure and find sections you've missed. This is a close cousin of keyword research scraping: a competitor's structure hints at query groups you haven't covered yet.
If instead you want to understand not one site's structure but who ranks at the top for your queries, that's SERP scraping — pulling the Google search results — which is a separate service we offer.
How to run your first crawl
- Point the crawler at your homepage. It starts there and follows internal links outward.
- Set the scope. Limit by subfolder, exclude parameters or faceted-navigation URLs, and cap crawl depth if the site is huge.
- Enable JavaScript rendering if the site is an SPA (React/Vue/Angular), or the crawler will only see the empty shell.
- Review the priority reports: response codes (find 404s and 5xx), redirect chains, duplicate titles/descriptions, and crawl depth.
- Export the tree and fix the structural issues — flatten deep sections, kill duplicate URLs, and repair broken internal links.
FAQ
What's the difference between a crawler and a scraper? A crawler discovers and walks URLs to map a site; a scraper extracts specific data from pages. In practice they overlap — most crawlers can also extract fields — but the intent differs. See crawling vs scraping for the full distinction.
Is crawling my own site safe?
Yes. Crawling a site you own is standard SEO practice. When crawling third-party sites, throttle your request rate and respect robots.txt so you don't overload their server.
How often should I crawl? For an active site, monthly is a reasonable baseline, plus an on-demand crawl after any major structural change or migration. Cloud crawlers can schedule this automatically.
Need the site structure or SERP data pulled at scale — hundreds of competitor catalogs, or ongoing monitoring rather than a one-off audit? scraping.pro can run it as a done-for-you data extraction service, delivering a clean structure export straight to your team.