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Core Concepts

Cubby is designed to be simple, but here are the key concepts to understand.

Apps

An app is a deployed project. Each app gets:
  • A unique URL: <app-name>.<username>.cubby.pro
  • Its own Postgres database (if needed)
  • Isolated container
  • SSL certificate

CUBBY.md

Every Cubby app should have a CUBBY.md file in its root. This file:
  • Provides context to AI tools building your app
  • Documents platform constraints
  • Explains available APIs and patterns
When you run cubby init, this file is created automatically.

Secrets

Environment variables are managed via cubby secrets. Secrets are:
  • Encrypted at rest
  • Injected at runtime
  • Never exposed in logs
Common secrets: API keys, database URLs (auto-provided), third-party service credentials.

Sharing

Apps can be shared with other Cubby users. Shared users:
  • See the app in their dashboard
  • Can access the app URL
  • Cannot modify the app or its secrets

Scale-to-Zero

Idle apps automatically sleep to save resources. When a request comes in:
  • App wakes up (cold start ~3 seconds)
  • Serves the request
  • Returns to sleep after idle timeout
Premium apps can be configured to stay warm.