Built Because SEO Tools Shouldn’t Cost a Fortune
ScreamingCAT is an open-source website crawler and technical SEO auditor built for professionals who want powerful tools without the price tag.
Good SEO Tools Are Expensive. They Don’t Have to Be.
Technical SEO crawlers are essential for anyone who manages a website. They find broken links, missing metadata, security gaps, and structural problems that hurt search visibility.
But the best desktop crawlers lock critical features — JavaScript rendering, Google integrations, unlimited crawling — behind annual licenses that cost hundreds of dollars. For freelancers, small agencies, and developers, that adds up fast.
We thought the core functionality of a website crawler shouldn’t be gated by price. So we built one that isn’t.
A Professional SEO Crawler. Open Source. Free.
ScreamingCAT is a desktop application that crawls websites the way search engines do — following links, extracting metadata, analyzing content, and detecting issues.
It runs natively on Windows, macOS, and Linux with a lightweight footprint. Built with Rust for backend performance and React for a modern interface, wrapped in Tauri for cross-platform desktop delivery.
The result: a fast, capable crawler that handles sites of any size — from a 50-page portfolio to a 100,000-page e-commerce store — without cloud dependencies or recurring fees.
Our Principles
Free means free
No freemium model. No feature gates. No “upgrade to unlock.” Every capability is available to every user from day one.
Your data stays yours
ScreamingCAT runs on your machine. Crawl data is stored locally. Nothing is sent to external servers unless you explicitly connect Google integrations.
Open source, open development
The source code is publicly available. Bug reports, feature requests, and contributions are welcome. Transparency builds trust — and better software.
Performance over bloat
Rust was chosen for the crawling engine because speed and memory efficiency matter when processing thousands of URLs. Tauri was chosen over Electron to keep the application lightweight.
The Tech Stack
| Layer | Technology | Why |
|---|---|---|
| Crawling engine | Rust + Tokio | Async, multi-threaded, memory-safe |
| HTML parsing | scraper (Rust) | Fast CSS selector-based extraction |
| JS rendering | headless_chrome | Full page rendering for SPAs |
| Database | SQLite (rusqlite) | Local storage, zero config |
| Frontend | React 19 + TypeScript | Modern, type-safe UI |
| Styling | TailwindCSS | Consistent, maintainable design |
| Desktop wrapper | Tauri 2 | Native feel, small binary, cross-platform |
| Data tables | TanStack Table + React Virtual | Handles 100K+ rows smoothly |
Contributing
ScreamingCAT is an open-source project. There are several ways to get involved:
- Report bugs — found something broken? Open an issue on GitHub
- Request features — tell us what you need via GitHub issues
- Submit code — pull requests are welcome for bug fixes, features, and improvements
- Spread the word — tell your SEO friends about a free alternative