What are the options to check the demo of Odoo?

There are two options available to check the demo of Odoo, ie demo.odoo.com, and Runbot. Please note runbot is a test platform.

How are the functionalities differ in demo and runbot?

demo.odoo.com helps the visitors to check the workflow of the latest stable odoo version without installing the instance. And since the instance gets updated automatically, all the data you created gets deleted during its updation.

Runbot will be helpful for testing upcoming features as well. Here one can access each version separately here and can test with demo data. This is used worldwide and all the features are merged to it for testing.

Where can we access demo instant?

One can access odoo instant for demo at https://demo.odoo.com

When each time I am using demo.odoo.com will it give the same instance?

Nope, Odoo serve you instances with lower traffic. So the instance may be differ each time you get into it.

Why is the data different each time when using these platforms?

Since the instances are used by large no users, the data may not be the same all time.