Crab vs CrawlObserver
Crab
crab.so
CrawlObserver
crawlobserver.comSide by side
| Figure | Crab | CrawlObserver |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | — | Yes |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | — |
| API | — | Yes |
| Plans published | 1 | 1 |
| Spec score · SEO Crawler Software | 8.2 (#12) | 8.6 (#5) |
| Spec score · SEO tools | 7.7 (#134) | 8.0 (#103) |
| Free plan | Yes | Yes |
| Integrations | The maker's comparison page lists Google Analytics, Search Console, PageSpeed Insights, and other integrations as “Soon.” | The page lists Google Search Console, Claude Code, and SEObserver under “Integrates with.” |
| JavaScript rendering | Crab can render JavaScript sites with headless Chrome, including React, Vue, and other single-page applications. | Rendering can be turned off, set to automatic, or always enabled; automatic mode detects frameworks including React, Vue, Next.js, and Nuxt. |
| Product | Crab is a desktop SEO crawler for auditing websites. | CrawlObserver is a lightweight SEO crawler with 45+ signals per page, cross-crawl comparison, and API control. |
| Site audit | Yes | Yes |
Plans
In their own words
CrawlObserver
CrawlObserver is a free private-beta SEO crawler available through web and API access. It reports more than 45 signals per page and describes audits without a page ceiling, including sites with 500K+ pages. Crawl comparisons identify added or removed URLs and changes to redirects, titles, and canonicals. Technical checks include redirect chains, internal PageRank, SimHash duplicate detection, and broken internal or external links. Internal authority-flow views help surface orphan pages, linking opportunities, and pages receiving too many links. JavaScript rendering can be off, automatic, or always enabled, with automatic detection for React, Vue, Next.js, and Nuxt. A REST API launches crawls and retrieves results. CrawlObserver says it follows robots.txt and crawl-delay, applies per-host delays, and blocks private IP ranges with post-DNS validation. Results are stored in ClickHouse.