Responsive images in Contao from a single upload
Define Contao image sizes once and render <picture> markup with WebP fallbacks from one high-resolution upload.
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Using Contao’s Template Override System to Customize Frontend Output Safely
Learn how to override Contao’s core templates by copying them into your theme’s /templates folder, allowing safe customizations that survive updates.
Choosing Between Twig and Legacy PHP Templates in Contao 4.9–5.x
Decision guide for Contao 4.9–5.x: why new projects should use Twig, how to migrate legacy PHP templates incrementally, and a concrete validation checklist with commands and caveats.
Extend Contao Without Editing Core Files Using Hooks
Register custom PHP classes at Contao extension points so core files stay untouched during updates.
symfonyContao Multilingual Fallback: What Happens When a Translation Is Missing
Configure language roots and page languages in Contao 4.x/5.x, then verify frontend fallback when a translation is unpublished or missing.
Contao Twig Template Architecture: Boundaries, Overrides, and Operational Checks
When Contao projects grow, mixing PHP and HTML in templates creates maintenance debt. This architecture note explains how Twig enforces boundaries, the smallest safe override, and how to verify cache and debug behavior.
Extend Contao Backend Tables Safely with the Data Container Array
Add custom fields to tl_page or other Contao tables using DCA without editing core files, then verify the change in the backend.
Contao Multilingual Strategy: Fallback vs. Full Translation
Contao lets you build multilingual sites by duplicating pages or using language fallback. Learn how to enable fallback, when it’s safe, and the trade‑offs between duplicating pages and translating only what matters.
Mastering Contao’s Form Generator: Conditional Fields and Server‑Side Validation
Contao’s Form Generator lets you create conditional fields and enforce server‑side validation without custom code. Follow this guide to set up a dropdown‑triggered field, verify frontend and backend behavior, and understand the trade‑offs.