Document Controllers — Implementation Workflows

Step-by-step workflows for building server-side DocType logic with full Python power. For exact syntax, see frappe-syntax-controllers.

Version: v14/v15/v16 | v15+: Supports auto-generated type annotations

Quick Decision: Controller vs Server Script?

NEED full Python (imports, classes, generators)?     → Controller
NEED external libraries (requests, pandas)?          → Controller
NEED try/except with rollback?                       → Controller
NEED frappe.enqueue() for background jobs?           → Controller
NEED to extend standard ERPNext DocType?             → Controller
Quick validation without custom app?                 → Server Script
Simple auto-fill or notification?                    → Server Script

Rule: ALWAYS use Controllers when you need a custom app. ALWAYS use Server Scripts for no-code prototyping.