Data · Tool

DB Diagram — Draw ERDs online for developers & students

dbdiagram.io is a free online ERD (Entity Relationship Diagram) tool — for anyone who needs to design a database schema quickly and share it easily. You write the schema in DBML (Markdown-like syntax), the ERD renders in real time beside it, and you export ready-to-run SQL (PostgreSQL, MySQL, SQL Server). Great for CS students doing coursework, backend developers designing new systems, or teams reviewing a schema before a sprint.

Why should every backend developer know how to draw an ERD?

  • Avoid painful refactors. Draw the ERD before coding → catch missing columns and wrong relationships on paper, not after 3 months of dev and 50 migrations.
  • Communicate with the team. One ERD is worth a thousand lines of docs. PMs, designers and QA all understand the data flow from a single diagram.
  • Pass interviews. “Design the schema for system X” shows up in ~70% of mid-level backend interviews. Knowing ERDs = answering confidently, sketching without fumbling.
  • Better school projects. A report with a clean ERD + auto-generated SQL → higher grades and happier instructors.
Free

Start drawing your ERD now

Open dbdiagram.io in a new tab. The first time you visit there’s a sample editor — type DBML, the ERD renders in real time, export SQL in one click.

https://dbdiagram.io/d
Click the button below to open the tool in a new tab — you can sign in, save your progress, and come back here to keep learning.
Open dbdiagram.ioSign in with Google for free to save diagrams. The free plan is enough for students and personal projects.

How to use dbdiagram.io in 3 steps

  1. 1

    Open the editor

    Click “Open dbdiagram.io” above to open the editor in a new tab. The first time you visit you’ll see a sample — delete it or keep it as a template.

  2. 2

    Write DBML

    Type the schema in DBML syntax — as simple as Markdown: define tables, columns, data types, primary keys and foreign keys. The ERD on the right updates in real time.

  3. 3

    Export SQL or share

    Click Export → choose PostgreSQL/MySQL/SQL Server to download a ready-to-run .sql file. Or Share → a public link to send your team / submit your assignment.

Frequently asked questions

What is an ERD?
An ERD (Entity Relationship Diagram) shows the tables (entities) in a database and the relationships between them (1-1, 1-n, n-n). It helps developers design a schema before coding, understand the data structure, and communicate with the team.
What is DBML?
DBML (Database Markup Language) is a text-based language for describing a database schema. The syntax is as simple as Markdown, easy to learn and easy to version-control with Git. dbdiagram.io uses DBML as input to render the ERD visually.
Is dbdiagram.io free?
Yes. The free plan is enough for students and personal projects: unlimited diagrams, SQL export, public share links. Paid plans add high-quality PDF/PNG export, private projects, and version history.
Why open a new tab instead of embedding it in ORA·tech?
dbdiagram.io uses Google OAuth to save diagrams to your account. Embedding it in an iframe on another domain blocks cross-origin cookies → login won’t work. Opening a new tab keeps your dbdiagram session so you can save your diagrams.
When should a CS student learn to draw ERDs?
After learning basic SQL (SELECT/INSERT/JOIN) and the concepts of primary key and foreign key. Drawing an ERD is the first step of any project with a database — including school projects, internships, or startups.

Next steps

Once your ERD is done, you’ll want to go deeper into backend databases. Here are related roadmaps on ORA·tech: