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SQL to ER Diagram Generator

Turn a SQL schema into a clear, interactive entity relationship diagram — free, with no signup, and without your schema ever leaving your browser.

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Why generate a diagram instead of reading the SQL

Onboarding

Hand a new engineer a diagram instead of a 40-table schema file and a shrug.

Documentation

Export SVG or PNG straight into your wiki, README, or design doc.

Code review

See exactly which tables a migration adds relationships between.

Spotting problems

A missing primary key or an unexpectedly isolated table stands out visually in a way it never does in raw SQL.

A diagram beats a wall of CREATE TABLE statements

A schema file tells you what the tables are. It doesn't tell you, at a glance, how they fit together — which table is the hub everything else hangs off, which pair forms a many-to-many junction, which relationship is actually optional. Reading that out of raw SQL means holding the whole schema in your head at once. A diagram just shows it.

This generator draws the diagram from your actual foreign keys and constraints — not a best guess from column names — so the cardinality badges, the identifying-vs-ordinary relationship lines, and the grouped containers all reflect what the database really enforces.

Free and private, not free-with-an-account

A database schema describes how a business works — table and column names alone can be sensitive. This generator has no server component for the diagramming itself: parsing, layout, and rendering all happen in your browser, so there's no account to create and no schema to hand over to a third party just to see what your own tables look like. The full detail on notation, grouping, and export options is on the main SQL Schema Visualizer page.

Frequently asked questions

Is this actually free, with no catch?

Yes. There is no account, no row limit, no watermark, and no paywall behind export. The tool is static client-side JavaScript — there is no server-side usage to meter, so there is nothing to charge for.

How is this different from other online ER diagram generators?

Most ER diagram tools — dbdiagram.io, SQLDBM, and similar — require an account and process your schema on their servers. This one parses and renders your SQL entirely in your browser: open the network tab, paste a schema, and watch the diagram appear without a single request leaving your machine.

What can I export?

SVG or PNG (light, dark, or transparent background, at up to 3x resolution) for documentation, the generated Mermaid erDiagram source to embed in GitHub or Notion, or the parsed schema as JSON for your own tooling.

Which SQL dialects can I generate a diagram from?

PostgreSQL, MySQL/MariaDB, SQL Server (T-SQL), SQLite, and BigQuery are all auto-detected from the SQL text, or you can pick one explicitly if your schema uses ambiguous syntax.

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