Crab

Crab is a desktop SEO crawler for site audits, combining technical checks with visual crawl mapping and page-level accessibility scoring. It suits site owners and technical SEO teams who want unlimited crawling on a local computer across Linux, macOS, or Windows. Its strongest case is broad, privacy-conscious auditing without a subscription; readers needing mature integrations or cloud collaboration should look elsewhere.

Overview

Crab audits the issues that routinely undermine discoverability: broken links, redirects, titles and meta descriptions, robots directives, hreflang, duplicate content, and structured data. Because it runs as a desktop application, crawl data is processed and stored on your machine, with the maker saying it is not sent to its servers or third parties. The app does send anonymous product analytics through PostHog, excluding crawl data, website content, and personally identifiable information.

JavaScript rendering through headless Chrome lets Crab inspect React, Vue, and other single-page applications rather than treating their initial HTML as the whole site. That makes it more suitable for modern front-end stacks than a crawler limited to static responses. The terms require you to crawl sites you own or have permission to crawl, follow robots.txt and crawl delays, and accept the software as-is without warranty.

Key features

Technical crawling and structure

Crab maps URL hierarchy and crawl depth, presents page relationships in an interactive link graph, and reports orphan pages. Those views turn a long issue list into a picture of how internal linking and depth affect a site, which is useful when planning navigation repairs or finding pages that receive no internal links. It can also produce a downloadable XML sitemap from crawled URLs, a practical output for sites that need a current sitemap file.

Accessibility scoring

Checks cover image alt text, form labels, and heading hierarchy. Each page receives an accessibility score from 0 to 100, giving teams a consistent way to prioritize page-level fixes alongside SEO work. The score is a triage signal, not a substitute for a full accessibility program, but it adds a dimension many specialist crawlers do not foreground.

Automation and source

Projects can run hourly, daily, weekly, or on a custom cron expression with timezone support. Recurring schedules fit monitoring work better than one-off audits, especially for sites that change frequently. Crab is open source, with source code on GitHub; questions are directed there, so support is community-oriented rather than a dedicated service desk.

Google Analytics, Search Console, PageSpeed Insights, and other integrations appear as “Soon,” so current workflows should assume exports and local analysis rather than connected reporting.

Pricing

Free — free, billed free forever. There is no free trial because the product is already free, and the plan has no URL limits, no subscriptions, and no premium tiers. This is an unusually straightforward fit for freelancers, agencies, and owners of large sites who need repeated crawls without quota-based upgrades. In exchange, there is no paid tier to provide differentiated support or future premium capabilities; teams wanting commercial service terms should evaluate alternatives.

Platforms

Crab supports Linux, macOS, and Windows. Downloads include a macOS DMG, Windows EXE, and Linux tar.gz installation instructions. The macOS app is signed and notarized by Apple, reducing friction for users who enforce standard macOS security checks.

Who it's for

Choose Crab if you need a desktop crawler for technical SEO, JavaScript-heavy sites, internal-link analysis, accessibility triage, and scheduled audits while keeping crawl content local. Its unlimited free plan is particularly compelling for consultants and organizations that cannot justify recurring crawler fees.

It is less suitable when your process depends on live integrations, hosted dashboards, vendor-backed support, or multi-user collaboration; those capabilities are not part of the current offering.

Pros and cons

• Pro: Unlimited URLs on a free-forever plan remove quota pressure on large websites.
• Pro: Headless Chrome rendering covers React, Vue, and other single-page applications.
• Pro: Local crawl storage keeps site data on the user's machine, while analytics exclude crawl content and personal information.
• Pro: Link graphs, orphan-page reporting, crawl-depth views, and accessibility scores add prioritization beyond basic error lists.
• Con: Integrations with Google Analytics, Search Console, and PageSpeed Insights are still marked “Soon.”
• Con: Support is routed to GitHub, and the terms provide no warranty.
• Con: There is no paid support or premium tier for teams seeking commercial service commitments.

Alternatives

For an open-source automated web-page audit across API, extension, desktop, and web environments, choose Lighthouse. If you want a self-hosted, MIT-licensed crawler with unlimited URLs and no account or API key, Open SEO Crawler is the better fit.

A1 Website Analyzer suits users who want a 30-day evaluation and a continuing free mode capped at 500 page URLs per website and 500 imported URLs. Beam Us Up is another completely free crawler with no stated limits. For browser-based crawling with a 100-URL basic cap, unlimited crawls, unlimited sites, and ads, consider Checkbot; its Professional yearly plan is $10.00 per year (billed $120 per year).

FreeCrawl offers free-forever unlimited URLs and no paid tier. Greenflare is a free, open-source GPLv3+ option. Netpeak Spider provides a free 500-URL mode with five threads and two devices per user on Windows and macOS, with paid upgrades for larger requirements.

For broader discovery, compare Crab with SEO Audit Software, SEO Crawler Software, and SEO tools.

Verdict

Crab is the right choice for SEO practitioners who want a capable, open-source desktop crawler with unlimited free URLs, JavaScript rendering, structural visualization, accessibility scoring, and local crawl storage. Choose it when privacy and cost matter more than connected reporting and vendor support. Look elsewhere if upcoming integrations, hosted collaboration, or formal support are essential to your workflow.