It is crucial to understand the execution order of Business Rules, Workflows, and Flow Designer. In many cases, the order of these events is important. Scripts, assignment rules, business rules, workflows, escalations, and engines all take effect in relation to a database operation, such as insert or update.

Detailed Execution order of scripts and engines

1. Start
2. Before Business Rules (Order < 1000)
   
   • Scripts configured to execute before the database operation with an order less than 1000.
3. Before Engines (No specific order)
   
   • Approval engine (for task and sys_approval_approver tables)
     
   • Assignment rules engine (for task tables)
     
   • Data policy engine
     
   • Escalation engine
     
   • Field normalization engine
     
   • Role engine (for sys_user, sys_user_group, sys_user_grmember, and sys_user_role tables)
     
   • Execution plan engine (for task tables)
     
   • Update version engine (for sys_update_xml table)
     
   • Data lookup engine inserts or updates
     
   • Workflow engine (for default workflows)
4. Before Business Rules (Order >= 1000)
   
   • Scripts configured to execute before the database operation with an order greater than or equal to 1000.
5. Database Operation
   
   • Insert, update, delete.
6. After Business Rules (Order < 1000)
   
   • Scripts configured to execute after the database operation with an order less than 1000.
7. After Engines (No specific order)
   
   • Label engine
     
   • Listener engine
     
   • Table notifications engine
     
   • Role engine (for sys_user, sys_user_group, sys_user_grmember, and sys_user_role tables)
     
   • Text indexing engine
     
   • Update sync engine
     
   • Workflow engine (for deferred workflows)
     
   • Trigger engine (for all Flow Designer flows)
8. Email Notifications (Based on weight)
   
   • Notifications sent on an insert, update, or delete
     
   • Event-based notifications
9. After Business Rules (Only active records, Order >= 1000)
   
   • Scripts configured to execute after the database operation with an order greater than or equal to 1000.
10. End

Bonus Read Business Rule Process Flow

Business rules run based on two sets of criteria.

• When to run the business rule in relation to a database operation.
• What record operation the business rule applies to.

Must Read

Controlling When Business Rules Run

Execution order of scripts and engines

Workflow Engine Overview

Script Execution in ServiceNow: An In-Depth Look