Draw ER diagrams online for free
Plan a database schema before writing SQL. Start from an ER diagram template, add entities and fields, mark primary and foreign keys, and connect tables with clear relationships.
Entity blocks ready to edit
Create tables with field names, types, primary keys, and foreign keys without setting up a separate database design app.
Relationship connectors
Show one-to-one, one-to-many, and many-to-many relationships clearly before implementation begins.
Useful before SQL
Align on schema structure with teammates before migrations, ORM models, or API work are written.
Share with your team
Use the ERD in specs, architecture docs, pull requests, and onboarding material.
How to make an ER diagram
Start with the main objects your product stores, then add fields and relationships. Keep the first diagram focused on structure, not every possible database constraint.
List your entities
Identify the core tables or objects, such as User, Order, Product, Invoice, or Project.
Add key fields
Add IDs, names, timestamps, and the fields that define each entity. Mark primary keys first.
Connect relationships
Draw how entities reference each other and mark foreign keys where ownership or lookup happens.
Review edge cases
Check whether relationships should be optional, unique, one-to-many, or represented by a junction table.
Common ER diagram use cases
Database schema planning
Design tables and relationships before creating migrations or writing SQL.
API and backend design
Clarify which resources exist, how they relate, and what data each endpoint should expose.
Data model documentation
Help new engineers understand an existing schema without reading every migration file.
Product feature planning
Spot missing entities and awkward relationships while a feature is still cheap to change.
ER diagram resources
ER diagram maker FAQ
Is CodePic free for creating ER diagrams?
Yes. You can open the ER diagram maker and start editing for free. Signing in is only needed for cloud saving and account features.
Can I use an ER diagram template?
Yes. The main call to action opens an editable ER diagram template with sample entities and relationships.
Can I show primary keys and foreign keys?
Yes. The template uses table-style blocks that can include PK and FK labels alongside field names and types.
Is this a database generation tool?
No. This page is for visual database design and documentation. It helps teams align before implementing the schema.
Ready to design your schema?
Open the free ER diagram maker, edit the sample schema, and make your database structure easier to review.
Start drawing an ER diagram