SEO Spider Software — a practical guide

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SEO spider software is a program that crawls your website the way a search engine bot does, page by page and link by link, and then lists the technical problems it finds: broken links, redirect chains, missing titles, duplicate pages, blocked URLs. For a small site you can do this for free. Screaming Frog's SEO Spider, the crawler searchers name most often, crawls up to 500 URLs without a licence, and a paid licence costs £199 a year. Prices and limits below were checked on each vendor's own page on 12 Nov 2026. This guide is desk research from official pricing pages and product documentation, not a lab test.

What an SEO spider actually does

A spider (also called a crawler or site auditor) starts at one URL, usually your homepage. It downloads the page, reads every link on it, adds those links to a queue, and repeats until it runs out of new URLs or hits a limit. While it goes, it records what it saw on each page.

The useful part is the report at the end. A typical crawl tells you:

• Status codes: which pages return errors (404 not found, 500 server error) and which links point to them.
• Redirects: temporary and permanent redirects, plus chains and loops that waste crawl time.
• Titles and meta descriptions: missing, duplicated, too long or too short.
• Headings and thin pages: pages with no H1, duplicate H1s or very little text.
• Duplicate content: exact copies of the same page under different URLs.
• Indexing signals: canonical tags, noindex tags, robots.txt blocks.
• Sitemaps: whether your XML sitemap matches the pages that actually exist.

Screaming Frog's product page, for example, lists broken links, redirects, page titles and meta data, duplicate content, XML sitemap generation, JavaScript rendering through a built-in Chromium browser, and connections to Google Analytics, Search Console and PageSpeed Insights.

A spider does not tell you how many people search for a keyword or who links to you. That is keyword research and backlink data, which live in all-in-one suites such as Semrush and Ahrefs. If you are unsure what those suites do, start with What Is Semrush or What Is Ahrefs.

Desktop crawlers vs cloud crawlers

There are two kinds of SEO spider software, and the difference matters more than the brand.

Desktop crawlers install on your computer and use its memory and processor. Screaming Frog, Sitebulb (desktop plans), Netpeak Spider and SEO PowerSuite's WebSite Auditor work this way. You pay for a licence, the crawl runs on your machine, and big sites need a machine with plenty of RAM. Screaming Frog states that its "unlimited" crawl depends on allocated memory and storage.

Cloud crawlers run on the vendor's servers. You enter a domain in the browser, the audit runs in the background, and it can repeat on a schedule. Ahrefs Webmaster Tools, the site audit inside Semrush, and Sitebulb Cloud are examples. You do not need a powerful computer, but you work within the vendor's crawl allowance.

For a small business site with a few hundred pages, either kind works. Desktop tools give you more control over each crawl. Cloud tools are easier to run monthly without thinking about it.

Which SEO spider tools exist, and what they cost

All figures were read on the official pages on 12 Nov 2026. Some vendors show prices only in pounds or euros, even when you pick dollars, so we quote what the page showed.

Ahrefs' paid Lite plan is $129 per month on monthly billing (from our verified data, checked 10 Nov 2026) if you later want its full toolset, not only the audit.

A few notes the table cannot hold:

• Screaming Frog is per user. Two people need two licences. The vendor offers lower per-licence prices from 5 licences up.
• Sitebulb lets you add extra users on Pro, and offers yearly billing at a discount.
• Netpeak Spider also sells yearly bundles with its other tools.
• Ahrefs Webmaster Tools counts credits only for HTML pages that return a 200 status; redirects and broken URLs do not use credits.
• Semrush shows site audit on its paid plans but did not publish crawl limits per plan on the pricing page when we checked, so we leave that number out.

To compare these against keyword and rank-tracking tools on one screen, use our SEO tool finder: match features to your budget. Tick "Site audit" and your monthly budget, and it will show which plans include a crawler and what each one costs per month.

How to run your first crawl: step by step

The steps below follow the same pattern in every desktop crawler. We use Screaming Frog as the example because its free version needs no account.

1. Download and install the tool. Screaming Frog runs on Windows, macOS and Linux. No licence key is needed for the free 500 URL mode.
2. Enter your homepage URL in the box at the top and press Start. Use the version your site really uses (https, with or without www).
3. Let it finish. Watch the progress bar; small sites finish quickly, large ones can take much longer.
4. Open the Response Codes tab and filter for client errors (4xx). Export the list with the "inlinks" so you know which page links to each broken URL.
5. Check redirects. Look for redirect chains (A to B to C). Change the internal link to point straight at the final URL.
6. Review Page Titles and Meta Description tabs. Fix missing and duplicated ones first. Length warnings are lower priority.
7. Look at indexability. Pages marked noindex or blocked by robots.txt should be pages you really want hidden. Mistakes here can hide important pages from Google.
8. Compare with your sitemap. Pages in the sitemap that the crawl never reached, or that return errors, need attention.
9. Fix, then crawl again. Save your list, make the changes in your CMS, and rerun the crawl to confirm the errors are gone.

If your site is built on a hosted builder, some of these settings sit inside the builder rather than in code. Our Framer Website Builder guide covers what a builder site controls for you.

When you need a paid crawler, and when you do not

You probably do not need to pay if:

• Your site has fewer than 500 URLs, including images, scripts and stylesheets the crawler may count. Screaming Frog's free mode and WebSite Auditor's free mode both stop at 500 URLs.
• You can verify your site in Ahrefs Webmaster Tools and the 5,000 credits a month cover it.
• You only check your site a few times a year, after a redesign or migration.

Google Search Console is also free and shows the pages Google itself has trouble with. It is not a crawler you control, but it tells you what the real Googlebot saw, which a spider can only imitate.

A paid crawler earns its cost when:

• Your site has thousands of URLs, such as an online store with filters or a blog with years of tag pages.
• You need to save crawls and compare them over time, or schedule audits.
• You need JavaScript rendering on a site built with React, Vue or Angular and want full control of the settings.
• You audit client sites. One annual licence for a desktop tool usually costs less than a year of an all-in-one suite.

An all-in-one suite makes more sense when you also need keyword research, rank tracking and backlink data. Then the site audit comes bundled and you avoid paying twice. If you are weighing AI-driven tools for this work, our LLM SEO Tools guide explains what they do and do not replace.

Common mistakes with crawl reports

A crawl report can list hundreds of warnings. Not all of them matter.

• Treating every warning as urgent. A title that is a few characters too long is rarely a problem. Broken internal links and pages wrongly set to noindex are.
• Crawling the wrong version. If you start from http while the site redirects to https, the report fills with redirects that are not real problems.
• Ignoring the URL limit. In free mode the crawl stops at 500 URLs, and the report only covers what it reached. Check the total before you assume the site is clean.
• Not recrawling. Fixes in a CMS sometimes do not apply to every template. A second crawl is the only way to be sure.

For more on how crawling fits into the wider job of getting found, see our Hosting, email and SEO guides.

FAQ

What are some good SEO tools?

For crawling, Screaming Frog SEO Spider, Sitebulb, Netpeak Spider and SEO PowerSuite's WebSite Auditor are the main desktop options, and Ahrefs Webmaster Tools offers a free cloud audit for verified sites. For keyword research, rank tracking and backlinks together, suites such as Semrush and Ahrefs bundle a site audit with those tools. Pick by site size and budget, not by brand name.

How to use Screaming Frog?

Install it on Windows, macOS or Linux, paste your homepage URL into the top bar and press Start. When the crawl ends, open the Response Codes tab to find broken links, then check redirects, page titles, meta descriptions and indexability. Export each list, fix the issues in your CMS and crawl again. The free version stops at 500 URLs, so larger sites need a licence.

Can ChatGPT do an SEO audit?

A chatbot can explain what a crawl report means and suggest fixes for issues you paste in. It cannot reliably crawl every page of your site, follow every internal link and record status codes the way dedicated SEO spider software does. Use a crawler to collect the data, then use an AI assistant to help prioritise and explain it, and check its suggestions against the actual pages.

What is technical SEO?

Technical SEO is the work that lets search engines find, crawl, render and index your pages: working links, sensible redirects, correct canonical and noindex tags, a clean XML sitemap, fast loading and a site structure that bots can follow. An SEO spider is the main tool for checking it, because it walks the site the way a search engine bot does and lists what breaks.