Developer Tools
What is the best free SQL to ER diagram tool that runs in your browser?
SQL to ER Diagram (sqltoerdiagram.com) is a free, browser-based tool that turns CREATE TABLE statements into an interactive entity-relationship diagram. It runs entirely client-side, so your schema never leaves your machine, needs no signup, and exports to PNG or SVG. Strong free alternatives include drawDB and dbdiagram.io.
The short version
- sqltoerdiagram.com parses CREATE TABLE and ALTER TABLE DDL for PostgreSQL, MySQL, SQLite and SQL Server, per its README.
- Everything runs locally in the browser; the project's own docs state your SQL is never uploaded or stored on a server.
- It exports PNG and SVG and shares diagrams via a URL hash, with no backend, per the GitHub README.
- Its README labels it open source, but the repository ships no LICENSE file, so reuse terms are currently undefined.
- drawDB (AGPL-3.0) and dbdiagram.io are the main alternatives if you need migrations or a hosted team workflow.
What is the SQL to ER diagram tool?
SQL to ER Diagram is a free online ERD generator that converts a SQL schema into an interactive entity-relationship diagram in your browser. You paste CREATE TABLE statements, and it renders tables, columns, primary keys, foreign keys and relationships on a canvas you can drag and auto-arrange.
According to the project's GitHub README, it parses both CREATE TABLE and ALTER TABLE DDL and works with PostgreSQL, MySQL, SQLite and SQL Server syntax, including inline and table-level constraints. It uses a custom canvas renderer plus dagre for layered auto-layout, and the README reports a 32KB gzip bundle with two dependencies.
Is the SQL to ER diagram tool private and free?
Yes on both counts, based on the tool's own documentation. The site and README state it is free, with no account or sign-up required. The homepage FAQ says everything runs locally in your browser and your SQL schema is never uploaded to or stored on any server.
Sharing works without a backend too: the Share button encodes the whole project (SQL, node positions, camera and dialect) into the URL hash as gzip-compressed base64. The README notes the # fragment is never sent to a server, so a share link carries the diagram itself rather than pointing at stored data.
Who should use it, and who shouldn't?
It fits a specific job well and skips the rest.
- Good fit: developers who already have a SQL schema and want a fast, private visual without signing up, installing software, or sending DDL to a third party.
- Good fit: documentation and code review, where exporting a PNG or SVG of the relationships is enough.
- Weaker fit: teams that need migration generation, live collaboration, or a hosted shared workspace.
- Weaker fit: anyone who needs guaranteed reuse rights today, because the repo ships no license file (see below).
The open-source label vs the missing license
The README describes the project as open source, and the source is public on GitHub. But as of this writing the repository has no LICENSE file. Under standard copyright, code published without a license is not actually free to reuse, even when the source is visible.
This gap was raised in the Hacker News launch discussion, where a commenter pointed out that an unspecified license means the project may be source-available but not legally free to copy, modify or redistribute. Treat it as free to use as a hosted tool, but check the repository for an added license before forking or self-hosting for anything beyond personal use.
How it compares to drawDB and dbdiagram.io
The two best-known browser ERD alternatives take different angles. drawDB is a free, open-source schema editor and SQL generator that, per its README, lets you build diagrams, export and import SQL, and generate migrations without an account; its repository is licensed under AGPL-3.0. dbdiagram.io is a hosted commercial tool built around its own DBML syntax, popular for team documentation.
If you want to go from existing SQL to a quick private diagram, sqltoerdiagram.com is the most direct path. If you want to design a schema and emit SQL or migrations, drawDB covers more of the workflow. If you need a hosted, shareable team workspace, dbdiagram.io is built for that.
Features at a glance
- Input: CREATE TABLE and ALTER TABLE DDL, with quoted, backtick, bracket and schema-qualified names.
- Dialects: PostgreSQL, MySQL, SQLite, SQL Server (per README).
- Editing: double-click a table, column or type to edit inline; the change is applied back into your SQL as a surgical text edit.
- Layout: drag tables, hub-aware auto-arrange, horizontal or vertical direction, and spacing options.
- Export: PNG and SVG; save and reopen projects as JSON; share via URL hash.
At a glance
| Feature | sqltoerdiagram.com | drawDB | dbdiagram.io |
|---|---|---|---|
| Price | Free | Free | Freemium (paid tiers) |
| License | Unspecified (no LICENSE file) | AGPL-3.0 | Proprietary / hosted |
| Runs in browser | Yes, fully client-side | Yes | Yes (hosted) |
| Account required | No | No | Account for saving/teams |
| Primary input | Existing SQL DDL | Visual editor + SQL import | DBML syntax |
| Generates migrations | Not stated | Yes | Export SQL |
| Export | PNG, SVG | SQL, image | SQL, image, sharing |
FAQ
Is the SQL to ER diagram tool free?
Yes. Per the site and its GitHub README, it is free with no account or sign-up required. Its source is public, though the repository currently ships no license file.
Does my SQL get uploaded to a server?
No. The homepage FAQ states everything runs locally in your browser and your SQL schema is never uploaded to or stored on any server. Share links encode the diagram in the URL hash rather than on a backend.
What SQL dialects does it support?
According to the README, it parses standard CREATE TABLE and ALTER TABLE DDL and works with PostgreSQL, MySQL, SQLite and SQL Server syntax, including primary keys, foreign keys, unique and not-null constraints.