A connection in Schemity is both a database target and a diagram. Each connection lives inside a workspace and is saved as one JSON file. You can design entirely offline, or attach connection details so Schemity can read a real database and turn its structure into an ERD. Either way, nothing leaves your machine - this is an ERD tool with no cloud.

The connection form, top to bottom

Every connection, whatever the engine, starts with the same fields:

  • ID - read-only, derived from the name.
  • Name - a label such as Production DB or Local dev.
  • DB type - the engine: PostgreSQL, MySQL, SQL Server, or SQLite.
  • Naming - the naming convention Schemity uses for generated names: snake_case or camelCase.
  • Conn method - how (or whether) Schemity connects:
    • None - offline design only. No live database; just draw.
    • Direct connection - connect over an accessible host and port.
    • SSH Tunnel - connect through a jump/bastion server (server engines only).
  • ENV type - an optional label: Local, Staging, or Production. It is purely a tag shown next to the connection in the connection list to help you tell environments apart; it has no effect on how Schemity connects.

When Conn method is anything other than None, a database-configuration block appears with the host, credentials, and engine-specific fields described in each engine’s guide.

Connection form with Conn method set to None - offline design only, no database fields

Connection form with Conn method set to Direct connection, showing host, port, and credential fields

Connection form with Conn method set to SSH Tunnel, adding the jump/bastion server fields

Connecting is a licensed feature

Designing offline (Conn method: None) is free. Connecting to a live database with Direct connection or SSH Tunnel - and the reverse-engineering, migrations, and SQL import that depend on it - is unlocked by a one-time desktop license.

Supported engines

How credentials are handled

Connections run from your machine directly to your database, so a host on localhost, a private VPN, or an isolated network all work. Passwords are never written into the JSON file - Schemity stores them in your operating system’s keychain. This is what keeps it an air-gapped ERD tool.

Read-only access

To browse a database without any risk of changes, right-click a saved connection and choose Open read-only. Schemity opens the diagram in a view that blocks edits and migrations.

Next

Pick your engine and follow its field-by-field guide, starting with Connect to PostgreSQL.