Scary Spider SEO: An Open Source SEO Crawler That Runs Locally

Lâm Tiên Hưng — Sun, 20 Sep 2026 09:21:43 +0000

SEO audits should not require uploading your entire website crawl to a third-party platform.

That is why I built Scary Spider SEO, a free, open-source desktop crawler for SEO, accessibility, and technical website audits.

It runs locally on Windows, macOS, and Linux. There are no crawl credits, hosted projects, or required accounts.

What It Does

Scary Spider SEO crawls a starting URL and helps you find issues such as:

Missing or poorly optimized title tags
Missing meta descriptions
Broken links and resources
Duplicate content
Canonical URL problems
Missing or duplicate H1 headings
Redirects and HTTP errors
Structured data issues
Security header problems
Accessibility violations
Mobile usability problems

The application explains each issue in plain language and suggests what to fix.

Why Build a Desktop Crawler?

Many SEO crawlers are hosted services. That can be useful, but it also means:

Your crawl data leaves your machine
You may need an account
Large crawls may require paid credits
Audits are often presented as reports instead of actionable data Scary Spider SEO takes a different approach.

The crawler runs on your computer, and the results are displayed in a searchable, sortable interface. You can inspect individual pages, filter issues, save crawl snapshots, and export data to CSV.

Built With Rust, React, and Tauri

The application uses:

Rust for the crawler backend
React for the interface
Tauri for the desktop application
SQLite-compatible data structures for crawl results
Headless browser rendering for JavaScript-enabled audits

Rust handles crawling, concurrency, resource collection, and page parsing. React provides the interface for exploring the results.

This combination makes it possible to keep the application lightweight while still supporting serious crawl workflows.

Configure Each Crawl

You can configure settings such as:

Crawl depth
Maximum page count
Request concurrency
Request timeout
Request delay
JavaScript rendering
Sitemap seeding
External link checking
Image checking
Accessibility auditing
Mobile usability auditing
Robots.txt compliance

JavaScript rendering is optional. Basic crawls can stay lightweight, while rendered crawls can inspect pages that depend on client-side JavaScript.

Useful for More Than SEO

Although the project started as an SEO crawler, a website audit often involves more than search rankings.

A page can have a correct title and still provide a poor experience for users. That is why Scary Spider SEO also supports accessibility and mobile usability checks when JavaScript rendering is enabled.

This makes it useful for:

SEO practitioners
Web developers
Site owners
Accessibility specialists
Technical marketing teams
Agencies performing client audits

Open Source and Local by Default

The project is available on GitHub:
GitHub repository link

You can inspect the code, report issues, request features, or contribute improvements.

The goal is not to replace every enterprise SEO platform. It is to provide a transparent, practical tool for people who want to inspect their websites without sending crawl data to another service.

Try Scary Spider SEO

Download the latest version for your operating system:
Download link
If you work on websites, build SEO tools, or care about local-first software, I would love to hear your feedback.

Try it, report an issue, and let me know which audit checks would be most useful in your workflow.

DEV Community: Lâm Tiên Hưng