VS Code Extension

VSCode

The Malloy VS Code Extension is the primary authoring environment for Malloy models. It includes schema browsing, query execution, language auto-complete, documentation, and result visualizations.

Installation

Download Visual Studio Code: If you don't already have it, download Visual Studio Code
Open the Extensions panel: Press Cmd+Shift+X (Mac) or Ctrl+Shift+X (Windows/Linux). Or open the Command Palette (Cmd+Shift+P / Ctrl+Shift+P) and type "Extensions: Install Extensions"
Install Malloy: Search for "Malloy" and click Install

Or install directly from the VS Code Marketplace.
Try the samples: Clone the malloy-samples repository:

Option A: In VS Code, use Clone Git Repository from the Start screen and enter:
```
https://github.com/malloydata/malloy-samples.git
```
Option B: From the command line:
```
git clone https://github.com/malloydata/malloy-samples.git
cd malloy-samples
code .
```
DuckDB is built into the extension, so you can run queries immediately—try opening any .malloy file in the faa or ecommerce folders.

VS Code Web (github.dev)

The Malloy Extension also works in VS Code Web environments like github.dev. Press . on any GitHub repository page to open it in the browser-based editor, then install the Malloy extension.

Limitation: VS Code Web only supports DuckDB with local files (CSV, JSON, Parquet). For BigQuery, Snowflake, or PostgreSQL, use VS Code Desktop.

Configuring Connections

There are two ways to configure database connections:

malloy-config.json (recommended) — a project-level config file checked into source control
VS Code Settings — user-level configuration via the Connections sidebar

When both exist, config file connections take priority. Settings connections are used as a fallback for any connection names not defined in the config file.

Connections Sidebar

The Malloy Connections sidebar shows all configured connections grouped by source:

Config — Connections from discovered malloy-config.json files. These are read-only in the editor; edit the JSON file directly to make changes.
Settings — User-defined connections from VS Code settings. Editable through the connection editor. If a settings connection has the same name as a config connection, it appears as "(shadowed)" since the config version takes priority.
Defaults — One entry per supported database type, using built-in defaults. Click to create a new settings connection from the default.

Click any connection to open the connection editor, or use the + button to create a new connection.

Project Configuration: `malloy-config.json`

Place a malloy-config.json file in the root of your project (workspace root). The extension detects it automatically and picks up changes whenever you save. In multi-root workspaces, each workspace root can have its own file with independent connection namespaces.

See Configuration for the full config file format, connection type properties, setup SQL, and environment variables.

VS Code Settings

You can also configure connections through the Connections sidebar or the command palette:

Open Command Palette: Cmd+Shift+P (Mac) or Ctrl+Shift+P (Windows/Linux)
Type: Malloy: Edit Connections
Click Add Connection and select your database type
Fill in the connection details

Sensitive values (passwords, tokens) are stored securely in your system keychain.

Connection Editor

The connection editor lets you view and manage individual connections:

Test — Verify the connection works with the current settings
Duplicate — Create a copy of an existing connection
Delete — Remove a settings connection

Config file connections open in a read-only view. You can still test them, but edit the JSON file directly to change settings.

Connection Settings

Setting	Description	Default
`malloy.globalConfigDirectory`	Directory containing a global `malloy-config.json`, used as a fallback when no workspace config file exists (e.g. `~/.config/malloy`)	`""`
`malloy.projectConnectionsOnly`	Only use workspace config file connections — hides global config, settings, and defaults	`false`

Database-Specific Setup

DuckDB

DuckDB runs locally with zero configuration. It reads Parquet, CSV, and JSON files.

// Local files (relative to .malloy file)
source: flights is duckdb.table('data/flights.parquet')
source: users is duckdb.table('../users.csv')

// URLs
source: remote_data is duckdb.table('https://example.com/data.parquet')

MotherDuck

Set your token as an environment variable before launching VS Code:

export MOTHERDUCK_TOKEN=your_token_here

Or configure via Malloy: Edit Connections with databasePath set to md:.

BigQuery

OAuth (recommended for development):

gcloud auth login --update-adc
gcloud config set project my-project-id --installation

Then add a BigQuery connection via Malloy: Edit Connections. Leave the service account field empty to use gcloud credentials.

Service account:

In Malloy: Edit Connections, click "Pick file" to select your service account JSON key.

Snowflake

Both password and RSA key authentication are supported via Malloy: Edit Connections.

You can also use Snowflake's connections.toml file:

Location: ~/.snowflake/connections.toml

[default]
account = "myorg-myaccount"
user = "analyst"
password = "your_password"
warehouse = "compute_wh"
database = "analytics"
schema = "public"

Database Support — Overview of all supported databases
Query existing models — Explore the malloy-samples to see Malloy in action
Build a semantic model — Create your first Malloy model from scratch