Publisher

<a href="https://github.com/malloydata/publisher/actions/workflows/build.yml"></a>

Publisher is the open-source semantic model server for Malloy. It serves Malloy models through REST and MCP APIs, enabling consistent data access for applications, tools, and AI agents.

Quick Start

git clone https://github.com/credibledata/malloy-samples.git
cd malloy-samples
npx @malloy-publisher/server --port 4000 --server_root .

Open http://localhost:4000 to explore the sample models.

Documentation

Full documentation is available at docs.malloydata.dev/documentation/user_guides/publishing:

• Getting Started - Setup, deployment options, configuration
• Database Connections - BigQuery, Snowflake, Postgres, DuckDB, and more
• Explorer - No-code visual query builder
• REST API - Build custom applications
• Publisher SDK - Embed analytics in React apps
• MCP for AI Agents - Connect Claude and other AI assistants

How the Pieces Fit Together

Malloy

The core compiler and query execution engine. Malloy compiles .malloy files into SQL, executes queries against databases, and returns structured Result objects. Malloy is a pure JavaScript/TypeScript library with no UI or serving capabilities—it's the foundation everything else builds on.

Repository: github.com/malloydata/malloy

Malloy Render

A visualization library that transforms Malloy Result objects into interactive tables, charts, and dashboards.

When Malloy executes a query, the result includes both data and rendering hints—tags like # bar_chart or # line_chart that indicate how the data should be displayed. Malloy Render interprets these tags and produces the appropriate visualization.

Built with: SolidJS and Vega/Vega-Lite. Available as both a JavaScript API (MalloyRenderer) and a <malloy-render> web component.

Repository: github.com/malloydata/malloy/packages/malloy-render

Publisher

An open-source semantic model server for Malloy. Publisher makes Malloy models accessible over the network and provides a professional UI for data exploration.

• Server: REST API for listing content, managing database connections, compiling models, and executing queries. Also provides an MCP API for AI agent integration.
• App: Web interface for browsing Malloy content, exploring models with a no-code query builder, and viewing results.

Publisher SDK

A React component library for building custom data applications powered by Publisher:

• API communication — Talks to the Publisher Server via REST
• Query execution — Submits queries and retrieves results
• Result visualization — Integrates Malloy Render to display results
• UI components — Pre-built pages for browsing projects, packages, models, and notebooks

The Publisher App is built entirely with the SDK, but the SDK is a standalone NPM package for building your own applications.

Architecture

Publisher consists of four packages:

| Package | Description | |---------|-------------| | packages/server | Express.js backend providing REST API (port 4000) and MCP API (port 4040). Loads Malloy packages, compiles queries, executes against databases. | | packages/sdk | React component library for building UIs that consume Publisher's REST API. | | packages/app | Reference implementation and production-ready data exploration tool built with the SDK. | | packages/python-client | Auto-generated Python SDK for the REST API. |

Development

This project uses bun as the JavaScript runtime.

git submodule init && git submodule update  # Get malloy-samples
bun install
bun run build:server-deploy
bun run start                               # Production server

bun run start:dev       # Dev server with watch
bun run test            # Run tests
bun run lint && bun run format  # Code quality

Community

• Join the Malloy Slack
• Report issues on GitHub