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The old Quickstart for SquareTag is still available. 

Concepts

Getting started with KRL can be a big leap because there are so many things that are different about programming in KRL for SquareTag and other CloudOS-based systems:

• To begin with KRL is a rule-based language. 
• KRL primarily follows an event-based programming model. 
• KRL programs execute with a cloud-based model; there is no way to execute them from the command line.
• KRL programs are loaded from the cloud using HTTP. 
• KRL programs execute in a system where identity is pervasive; all events are raised on behalf of a specific entity.
• KRL programs have built-in, entity-specific persistent storage; there is no need for external databases.

The result of these properties is a programming model that more closely resembles programming cloud-based persistent objects than anything else. We call these persistent computational objects "picos". 

KRL is executed by the Kinetic Rules Engine (KRE), a open-source, cloud-based rule processing system. All of the properties listed above are present in any KRE system. 

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