Liam — Auto-Generate ER Diagrams from Your Database

Introduction

Liam is an open-source tool that automatically generates interactive entity-relationship diagrams from your database schema. Point it at a PostgreSQL database, a Prisma schema file, or other supported sources, and it produces a clean, navigable ER diagram in your browser. The diagrams are rendered with React Flow for smooth panning, zooming, and exploration of complex schemas.

What Liam Does

• Generates ER diagrams automatically from live database connections or schema files
• Supports PostgreSQL, Prisma, and other schema sources
• Renders interactive diagrams with zoom, pan, and entity selection
• Shows table columns, types, primary keys, and foreign key relationships
• Exports diagrams as images or embeddable web components

Architecture Overview

Liam is built as a TypeScript/Node.js application with a React frontend powered by React Flow for diagram rendering. The backend connects to database sources or parses schema files (Prisma, SQL dumps) to extract table definitions, column types, and relationships. This metadata is transformed into a graph layout using automatic positioning algorithms that minimize edge crossings and optimize readability. The frontend renders each entity as an interactive card with expandable column details and clickable relationship lines.

Self-Hosting & Configuration

• Run via npx for instant use without installation
• Connect directly to PostgreSQL databases with a connection string
• Import Prisma schema files, tbls YAML output, or raw SQL DDL
• Deploy the web UI as a static site or run it locally
• Customize colors, layout direction, and entity grouping via configuration

Key Features

• Zero-config ER diagram generation from a database URL or schema file
• Interactive React Flow-based UI with smooth navigation
• Automatic layout algorithm for readable diagram arrangement
• Support for PostgreSQL, Prisma, Rails, and tbls schema formats
• WebAssembly-powered parsing for client-side schema processing

Comparison with Similar Tools

• DBeaver — database client with basic ER views; Liam provides a dedicated, polished diagram experience
• dbdiagram.io — requires manual DBML input; Liam auto-generates from your actual schema
• pgAdmin — PostgreSQL-specific admin tool; Liam focuses on beautiful, shareable diagrams
• ChartDB — schema diagram editor; Liam emphasizes automatic generation over manual editing
• DataGrip — commercial IDE with ER features; Liam is free, open-source, and web-based

FAQ

Q: Which databases does Liam support? A: PostgreSQL is the primary target. Prisma schemas, tbls YAML, and SQL DDL files are also supported.

Q: Can I share the generated diagrams? A: Yes. Export as PNG/SVG images or deploy the web UI for interactive sharing with your team.

Q: Does Liam handle large schemas? A: Yes. The React Flow renderer handles hundreds of tables with smooth performance. You can filter and group entities for focus.

Q: Is it a one-time generation or does it stay in sync? A: You regenerate diagrams when your schema changes. Continuous sync is not automatic but the generation is fast.

Sources

• https://github.com/liam-hq/liam