Can Sanity use external databases like MongoDB or PostgreSQL?

No, Sanity does not allow you to replace its core database with an external database like MongoDB or PostgreSQL.

Sanity operates as a fully-managed platform with its own proprietary database called the Content Lake. This is a cloud-hosted, content-optimized JSON database that's specifically designed for structured content management with features like:

• Real-time collaboration and updates
• Built-in revision history
• Referential integrity between documents
• Atomic mutations and transactions
• Global CDN distribution
• GROQ and GraphQL query support

The Content Lake is a fundamental part of Sanity's architecture - it's not something you can swap out or configure to use a different database backend. All your content is stored in Sanity's infrastructure, which is hosted on Google Cloud Platform.

However, you can integrate external databases with Sanity:

If you need to work with data from MongoDB, PostgreSQL, or other databases, you have a couple of options:

1. Sync external data into Sanity - You can use the Sanity Connect pattern to create sync plugins that pull data from external systems into Sanity documents. This is commonly done for e-commerce platforms like Shopify, but the same approach works for any external data source. You'd typically use webhooks or cron jobs to trigger syncs, and then your frontend can query everything from Sanity's API in one place.

2. Query external databases alongside Sanity - In your application layer, you can fetch data from both Sanity's Content Lake and your external database, then combine them as needed. You could use Sanity Functions (serverless compute within Sanity) to handle this logic and create custom API endpoints that merge data from multiple sources.

The key insight is that Sanity is designed as a content platform, not a general-purpose database replacement. It excels at managing structured content with editorial workflows, but you're meant to use it alongside other data systems in your stack rather than replacing them entirely.