Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Database Schema Visualizer
Visualize database schema as ER diagrams from SQL CREATE TABLE statements
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ER Diagram
Paste CREATE TABLE statements and click Visualize
Tables
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Columns
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Relationships
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Diagram
ERD
What Is a Database Schema Diagram?
An entity-relationship diagram (ERD) visually represents the structure of a database, showing tables as boxes with their columns, primary keys, and the relationships (foreign keys) connecting them. It helps developers understand data models at a glance.
How to Use This Tool
- Paste your SQL DDL — Enter one or more CREATE TABLE statements in the input area.
- Click Visualize — The tool parses your DDL and renders an entity-relationship diagram.
- Inspect the diagram — View tables as boxes with columns, primary keys (PK), and foreign key (FK) relationships as connecting lines.
- Export the result — Download your diagram as SVG, PNG, or JPG for use in documentation or presentations.
- Check summary stats — The summary panel shows table count, column count, and relationship count at a glance.
Frequently Asked Questions
What SQL dialects are supported?
The parser supports MySQL, MariaDB, PostgreSQL, and SQLite CREATE TABLE syntax, including PRIMARY KEY, FOREIGN KEY, AUTO_INCREMENT, NOT NULL, UNIQUE, DEFAULT, and CHECK constraints.
Can I visualize existing database schemas?
Yes. Most database tools can export DDL (SHOW CREATE TABLE in MySQL, pg_dump —schema-only in PostgreSQL). Export your schema and paste the output directly into this tool.
Is my schema data sent to a server?
No. All parsing and rendering happens locally in your browser. Your SQL schema data never leaves your device.
What export formats are available?
You can export the diagram as SVG (scalable vector), PNG (raster image), or JPG (compressed image). SVG is ideal for documentation, while PNG and JPG work well for embedding in presentations.
Can I visualize complex schemas with many tables?
Yes. The tool can handle schemas with dozens of tables and relationships. Use example presets like E-commerce or School to see how complex schemas are rendered.
Last updated: 17 Aug 2026
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