MDX SEO Validator is a free VS Code extension that validates SEO metadata in MDX/Markdown files with a live Google search preview.
- for
- Developers writing content-driven sites with Next.js, Astro, or Remix
- pricing
- free
- license
- MIT
Key features
- Live Google Search Preview — Shows exactly how the page will appear in Google results as you type, with character counts and favicon.
- SEO Score & Validation — Provides an overall 0-100 SEO score and detailed rule-by-rule feedback for meta tags, content, images, and links.
- Framework-Aware Detection — Automatically detects favicons and metadata for Next.js, Astro, Remix and generic projects.
- Real-Time Updates — Validates title length, description, heading hierarchy, alt text and more on each keystroke (≈300 ms debounce).
- Configurable Settings — Allows framework selection and site domain configuration via VS Code settings.
- Vanilla JS Webview — Uses a lightweight inline HTML/CSS/JS webview for fast load times (~10 KB).
Use cases
- Validate SEO of a Next.js blog post while writing the MDX file
- Ensure consistent SEO metadata across an Astro documentation site
- Check title, description, OG tags and heading hierarchy for marketing copy before publishing
MDX SEO Validator vs alternatives
 MDX SEO Validator |  AITDK SEO Extension | |
|---|---|---|
| Best for | Real-time SEO checks inside VS Code | Comprehensive SEO auditing outside the editor |
| Pricing | Free | Free |
| DevHunt upvotes | 0 | 26 |
| Launched | Jan 2026 | Jun 2024 |
- MDX SEO Validator vs AITDK SEO Extension: Provides broader site-wide SEO analysis and keyword tools, but is a separate browser extension rather than an IDE integration.
MDX SEO Validator FAQ
Do I need to leave VS Code to check SEO?+
No, the extension provides live validation and a Google preview directly inside the editor.
Which frameworks are supported?+
It automatically detects Next.js (App and Pages routers), Astro, Remix and generic projects.
Can I configure the site domain shown in the preview?+
Yes, set "seo.siteDomain" in VS Code settings to your domain.
Is the extension open source?+
Yes, it is released under the MIT license and the source is on GitHub.
What SEO rules are checked?+
Title length, meta description length, Open Graph tags, heading hierarchy, alt text for images, internal link count, and more.
How is the extension built?+
It uses vanilla HTML, CSS and JavaScript for the webview, avoiding heavy frameworks for performance.
Summarized by DevHunt from marketplace.visualstudio.com · Oct 16, 2026. Details may change; check the official site.
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