Hey Product Hunt, I'm Cord. Colton and I are the makers of DB Planner.

DB Planner started as a DBML viewer and grey into a full system design board. The text stays the source of truth: you write DBML for the schema and Mermaid for the diagrams, and every table, class, and flowchart step becomes a card on one shared canvas. Drag anything anywhere, the source never changes.

What's on the board today:

Interactive ER diagrams parsed live from DBML, split across as many files as you like. References resolve across files with no import lines.
Mermaid class diagrams and flowcharts render as cards beside your tables. Frame and cross links can span both, so "this flowchart step writes to the orders table" is a sentence the board can finally say.
Real time collaboration with live cursors, presence, and shared editing in a proper built in code editor.
Import a SQL dump from Postgres, MySQL, or MSSQL. Export C# models, SQL, DBML, Mermaid, or export the board itself as an image. An image can be the whole board, just the schema, or just the diagrams.
Annotate everything with sticky notes, freehand drawing, arrows, shapes, text, and images on the board, plus table and column comments that live right in the DBML.
An MCP server, so Claude or Cursor can read your schemas, edit them, and even lay out the board.
A template marketplace, where you can start from a schema somebody has already worked out, or publish your own, sell it, and keep 90%.

Pricing is simple: a free plane (1 project, 10 files, no card needed), Pro at $5, which lets you create organizations, and added seats are $5 after.

Give it a try on the free plan and let us know what you think. We would love any feedback or questions.

Thanks for taking a look!

- Cord and Colton at DB Planner

Interactive ER diagrams parsed live from DBML, split across as many files as you like. References resolve across files with no import lines.
Mermaid class diagrams and flowcharts render as cards beside your tables. Frame and cross links can span both, so "this flowchart step writes to the orders table" is a sentence the board can finally say.
Real time collaboration with live cursors, presence, and shared editing in a proper built in code editor.
Import a SQL dump from Postgres, MySQL, or MSSQL. Export C# models, SQL, DBML, Mermaid, or export the board itself as an image. An image can be the whole board, just the schema, or just the diagrams.
Annotate everything with sticky notes, freehand drawing, arrows, shapes, text, and images on the board, plus table and column comments that live right in the DBML.
An MCP server, so Claude or Cursor can read your schemas, edit them, and even lay out the board.
A template marketplace, where you can start from a schema somebody has already worked out, or publish your own, sell it, and keep 90%.

DB Planner

Design your schema and your system, together.

Design your schema and your system, together.