If you use a GNU/Linux distribution, almost any text editor will respect structure and format.Standard Notepad is considerably unreliable when it comes to respecting structure and format, and can bring a bunch of unnecessary headaches. If you use Microsoft Windows, consider using Notepad++.Paradox Node Editor - Visual Application for Editing EU4 Missions.CW Tools for VS Code - Provides interactive validation as well as features such as completion, localisation generation and hover info while you write.JoroDox mod making tool (wiki page: JoroDox mod making tool).The Validator - Find errors quickly and with minimal pain! (Wiki Page: The Validator).