dbdiagram.io vs SchemaSpy

dbdiagram.io creates database relationship diagrams by letting users describe schemas in DBML, its Database Markup Language. Developers and data analysts can design diagrams in the web app, while its cloud version imports and exports SQL. Supported databases include PostgreSQL, MySQL, SQL Server, Oracle, Snowflake, and BigQuery; Oracle import uses Oracle 19c syntax. Free users can filter tables in the default view, while saving multiple customized views requires Personal Pro. Personal Pro also includes an AI Assistant for schema design, modification, and optimization through natural language, with a monthly token quota. The editor extension supports VS Code, Cursor, Windsurf, and other Open VSX-based editors, with live ERD previews from DBML files. A CLI syncs local DBML files with diagrams and can publish documentation to dbdocs.io from a terminal or CI pipeline. Free diagrams allow public link sharing; password protection and private mode require Personal Pro or Team. Free costs nothing; Personal Pro is $20 a month and Team is $60 a month. A 7-day Team trial requires a payment method and automatically charges when it ends.

SchemaSpy is a free, open-source command-line application that reads database metadata and creates shareable HTML documentation. It generates entity-relationship diagrams from an existing database, collects structural statistics, and can export those statistics to Excel or CSV. Reports can identify design anomalies such as missing indexes, implied relationships, and orphan tables. The project says it supports over a dozen databases directly and can work with others through JDBC drivers. Documentation generation can be placed in a CI/CD workflow, and SchemaSpy can run against an empty database replica because it reads structural information. There is no graphical interface: distribution is through a JAR file or Docker image. Installation requires Java, a database JDBC driver, and viz.js or Graphviz for relationship diagrams. The JAR excludes drivers, while the Docker image includes drivers for MySQL, MariaDB, PostgreSQL, and jTDS for MSSQL. The listed plan price is free.