entitymodel.com
Free, open-source data modeling and ER diagrams in your browser.
EntityModel.com is a free, MIT-licensed data modeling tool that runs in the browser. You draw entity-relationship diagrams in crow's foot notation, then generate SQL DDL for PostgreSQL, MySQL, Snowflake, and Databricks, along with DBML, Mermaid, dbt, and PDF design documents from the same model. It needs no account and no install, works offline, and keeps your models in your browser unless you export or share them.
Desktop modeling suites are expensive and heavy, and lightweight diagram tools stop at the picture. EntityModel keeps conceptual, logical, and physical models in one file, generates the DDL and migrations, and saves models as plain JSON you can review in a pull request.
- Conceptual, logical, and physical models as tabs, with derive, compare, and generated migration SQL
- Import from SQL DDL or DBML; reverse-engineer from Databricks, Snowflake, PostgreSQL, and MySQL
- Export SQL DDL, DBML, Mermaid, dbt schema.yml, ODCS data contracts, JSON Schema, Avro, PDF, PNG, and SVG
- Reference data, glossary, naming standards, and live validation in an Issues panel
- Models saved as plain JSON for Git and pull-request review
- CLI and MCP server so AI agents such as Claude can design and edit models
- Tested on models with 2,000 and 5,000 tables; installable as an offline app
- Free with no usage limits; shared workspaces with a free account
Data architects and modelers who want a lighter alternative to desktop suites, analytics and data engineers who need logical models, DDL, and dbt tests from one place, and software engineers documenting a database.