Online ER diagram tool

Entity relationship diagrams, online.

LetDraw is an ER diagram tool that turns your SQL DDL into an entity relationship diagram with crow's foot notation, right in the browser. Paste your CREATE TABLE statements or draw tables by hand, then edit every table, column and relationship. Free to start.

Make an ER diagram How it works
Shop schema · ER diagram
users idPK emailvarchar namevarchar orders idPK user_idFK totaldecimal created_attimestamp order_items idPK order_idFK qtyint
Step by step

How to make an ER diagram in LetDraw

From a schema file to a database diagram you can share, in a few minutes and without installing anything.

  1. Open Generate from Code

    Generate from Code is a Pro feature. Paste your CREATE TABLE statements into the dialog. The format is detected for you, and a preview appears right away.

  2. Pick the relationship style

    Choose crow's foot for ER cardinality, or a straight line, arrow or smart routing, and see the preview update.

  3. Edit on the canvas

    Every table, column and relationship is a normal shape. Move tables, rename columns or add new entities by hand.

  4. Share or export

    Send a link, review the schema together in real time, or export the ER diagram as PNG, SVG or PDF.

Schema in, diagram out

ERD from SQL in one paste

The SQL importer reads CREATE TABLE statements in Postgres, MySQL and standard SQL, picks up primary keys, foreign keys, unique and not null columns, and lays the tables out as clean grids. Foreign keys become relationships with crow's foot ends, inferred from the key columns.

  • SQL DDL import with PK, FK, unique and not null markers
  • Crow's foot notation as native arrowheads: one, zero or one, zero or many, one or many
  • Mermaid ER import and export, plus AI drafts from a description
Try it now
CREATE TABLE orders ( id int PRIMARY KEY, user_id int REFERENCES users(id) ); users idPK email orders idPK user_idFK
What people draw

An entity relationship diagram for every stage

Use the ER diagram tool to plan a new database, document an old one or explain one to a new teammate.

New schema design

Sketch entities and relationships before the first migration, starting from the Database Schema template.

Documenting a database

Export the DDL from an existing database and get a database diagram for your wiki or handbook.

Migration reviews

Put the before and after schema side by side and talk through foreign keys and cardinality with comments.

Onboarding

Give new developers one picture of how users, orders and payments connect before they read the code.

Query plans

Paste an EXPLAIN plan in JSON and see the query as a plan tree next to your schema.

Teaching data modeling

Explain one-to-many and many-to-many relationships with crow's foot ends students can read at a glance.

Questions

ER diagram tool FAQ

Is LetDraw's ER diagram tool free?
Drawing ER diagrams by hand is free: the Free plan includes the full canvas, templates such as Database Schema, shape libraries and export to PNG, SVG and PDF, with no credit card. Generate from Code, which turns SQL into a diagram, is included in Pro.
Can I generate an ERD from SQL?
Yes, with Pro. Paste CREATE TABLE statements into Generate from Code and LetDraw builds the tables, columns and foreign key relationships as editable shapes. It reads the schema (DDL), not the data in your tables.
Does it support crow's foot notation?
Yes. Crow's foot ends are built-in arrowheads: many, one or many, one and only one, zero or one, and zero or many. You can set them on any line, not only on imported diagrams.
Is my schema uploaded when I import SQL?
No. The SQL is parsed in your browser to build the diagram. The diagram itself is saved like any other document, in your browser as a guest or in your account when you sign in.

More diagrams you can make

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Your next ER diagram is one paste away.

Open LetDraw in your browser and drop in your schema, or draw the tables by hand. Fast, and nothing to install.