Process order for automation rules and Apex triggers

  1. Old record loaded from database (or initialized for new inserts)
  2. New record values overwrite old values
  3. System Validation Rules (If inserting Opportunity Products, Custom Validation Rules will also fire in addition to System Validation Rules)
  4. All Apex before triggers (EE / UE only)
  5. Custom Validation Rules
  6. Record saved to database (but not committed)
  7. Record reloaded from database
  8. All Apex after triggers (EE / UE only)
  9. Assignment rules
10. Auto-response rules
11. Workflow rules
12. Processes
13. Escalation rules
14. Parent Rollup Summary Formula value updated (if present)
15. Database commit
16. Post-commit logic (sending email)