Tech Stack Tier

The classification of operational software tools into three strategic levels based on their role in the business: 

• Tier 1 systems are the foundation. They store the data that define the operations (ERP, CRM, and HRIS). 
• Tier 2 systems are the workflow layer. They move work between people and departments.
• Tier 3 systems are point solutions. They solve specific, bounded operational problems. 

The correct architecture has very few Tier 1 systems, a purposefully selected set of Tier 2 systems, and a regularly audited Tier 3 system catalog.