Drupal Render API

Philosophy: Configuration First -- Prioritize render arrays (the declarative approach) over raw HTML output. Render arrays are data structures that get processed, cached, and themed automatically.

I need to...

Task	Guide
Understand when to use render arrays vs other approaches	Render API Overview
Learn render array structure and syntax	Render Array Structure
Know what #type, #theme, #markup mean	Render Properties
Find the right render element for my output	Core Render Elements
Use form elements outside forms	Form Render Elements
Attach CSS/JS libraries to my render array	Attachments
Add cache metadata to improve performance	Cache Metadata in Render Arrays
Use the Renderer service programmatically	The Renderer Service
Pass render arrays to Twig templates	Twig Integration
Modify variables before they reach Twig	Preprocess Functions
Create theme hooks and suggestions	Theme Hooks & Suggestions
Defer expensive rendering for better caching	Lazy Builders & Placeholders
Create my own render element plugin	Custom Render Elements
See common render array patterns	Render Array Patterns
Understand main content renderers	Main Content Renderers
Follow best practices	Best Practices & Patterns
Avoid common mistakes	Anti-Patterns & Common Mistakes
Ensure security and performance	Security & Performance
Find core render files and documentation	Code Reference Map