I was building a simple Astro landing page for my dad and hit the usual wall — which CMS do I use?
Pages CMS was too simple. Payload was too much setup for a 5-page site. Sanity felt like overkill. Contentful wanted my credit card. Nothing had the combination I needed: multi-tenant, multi-project, git-based, self-hosted, with a proper media editor.
So I did the rational thing and spent the next few days vibecoding my own CMS instead of finishing the landing page.
The result: Kern CMS
The core idea is simple — your content lives as JSON files directly in your GitHub repository. No database, no external API, no vendor lock-in. Your data is always yours.
What it actually does:
<ul>
<li>Multi-tenant — one instance, unlimited clients</li>
<li>Multi-project — manage everything from one place</li>
<li>Media editor — cropping, compression, R2 + S3 support</li>
<li>Schema auto-inference — drop a JSON file in, Kern figures out the types</li>
<li>AI Hardcoded strings -&gt; template content files</li>
<li>GitHub App setup in one click</li>
<li>Works with Astro and maybe more (need to test)</li>
</ul>
AGPL 3.0 licensed. Self-hosted. Free forever. No seat pricing. No monthly bill.
🌐 <a href="http://kerncms.com" target="_blank" rel="noopener nofollow">kerncms.com</a>
💻 <a href="https://github.com/fiioonnn/kerncms" target="_blank" rel="noopener nofollow">https://github.com/fiioonnn/kerncms</a>
<img src="https://media.daily.dev/image/upload/s--TUTcowb4--/f_auto/v1777286645/ugc/content_b1e69354-0c11-48e6-900a-967c872ed2bc?_a=BAMAMiWQ0" alt="Figma Image 13 (1).png">
<img src="https://media.daily.dev/image/upload/s--y7sbKcH6--/f_auto/v1777286637/ugc/content_2a525fb6-59d0-4eab-af92-61d759297c29?_a=BAMAMiWQ0" alt="Media Filters.png">
Would love feedback, contributions, or just someone to tell me what I missed.

fiioonnn

Kern CMS is a self-hosted, git-based CMS built out of frustration with existing options. Content is stored as JSON files directly in a GitHub repository — no database, no external API, no vendor lock-in. Key features include multi-tenant and multi-project support, a media editor with cropping/compression and R2/S3 storage, schema auto-inference from JSON files, AI-assisted hardcoded string conversion, and one-click GitHub App setup. It's AGPL 3.0 licensed, free forever, and currently works with Astro. The author is seeking feedback and contributions.

I built a self-hosted, git-based CMS because nothing out there had everything I needed