Most SEO crawlers work by sending requests from remote servers. But what happens when a website relies heavily on JavaScript, requires authentication, runs on localhost, or is protected by a WAF?
I wanted to explore a different approach.
That's why I built SEOFixi — a technical SEO crawler that runs directly in the Chrome browser.
Why a browser-based crawler?
The idea was to use the actual browser environment instead of relying entirely on external crawling infrastructure.
This brings several practical advantages:
- Fetch-based crawling — inspecting pages and resources through the browser environment.
- SPA support — working with JavaScript-powered websites and dynamically rendered content.
- Existing browser sessions — auditing pages accessible through an authenticated session.
- Localhost and staging — testing websites before deployment.
- Privacy-first processing — website data stays on the user's machine instead of being uploaded to external servers.
This architecture is also designed with GDPR-related privacy requirements in mind.
More than just crawling
SEOFixi currently includes 80+ technical SEO checks covering:
- Titles, meta descriptions and headings.
- Broken links and redirects.
- Indexation and canonical URLs.
- Robots directives and structured data.
- Resources and performance diagnostics.
- Synthetic Core Web Vitals indicators.
It also generates PDF and Excel audit reports directly in the browser.
The engineering challenge
The hardest part wasn't implementing individual SEO checks. It was combining crawling, page discovery, JavaScript rendering, browser security restrictions and reporting into one consistent workflow.
I deliberately focused on technical SEO diagnostics rather than building another all-in-one marketing platform.
Not everyone needs an expensive enterprise SEO subscription just to understand what's wrong with their website.
What's next?
SEOFixi is a working Chrome extension, and I'm now looking for developers, SEO specialists and website owners willing to test it.
I'd especially appreciate feedback from people working with JavaScript-heavy websites, authenticated environments and technically complex projects.
Try SEOFixi:
https://seofixi.com
Chrome Extension:
https://chromewebstore.google.com/detail/seofixi-%E2%80%94-technical-seo-a/dpkkllafhcmemjcmebaeclnjhpcooib
I would appreciate any feedback!
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