What is ContentBlocks?

ContentBlocks is a modular page builder for Symfony. It lets editors compose rich content — sections, columns and blocks — directly inside your application, with a live in-context preview, without turning your app into a CMS.

It ships as two Composer packages:

Package	What it gives you
klehm/content-blocks	The core: Doctrine entities, the admin builder UI (Live Components + Stimulus), the ContentAreaType form, and the extensible block-type system.
klehm/content-blocks-kit	An optional set of 17 ready-to-use, self-contained blocks (title, text, image, gallery, button…). See the Block Kit.

The core idea

The central entity is ContentArea — a generic, titleless, slug-less container of sections. It is not a page. It has no URL. Your application owns those.

ContentArea  →  Section  →  Column  →  Block

You attach a ContentArea to your own entity via a plain Doctrine relation:

#[ORM\OneToOne(targetEntity: ContentArea::class, cascade: ['persist', 'remove'])]
private ?ContentArea $contentArea = null;

That's the whole integration contract. A Page, a Product, a Category — anything with a public URL can carry editable content areas. ContentBlocks handles the structured content and the editing experience; you keep routing, templates, SEO and auth.

In-context editing, real preview

Most builders show you an approximation and hope the front-end matches. ContentBlocks instead opens your actual public page in an iframe and injects the editing UI into it. Editors manipulate the real rendered markup — so the preview can't drift from production.

Rendering has two modes, auto-detected per request:

• Public — clean, published HTML. No markers, no overlay. This is what visitors get.
• Preview — the same HTML plus editing markers and the overlay script, shown only when AccessCheckerInterface::canEdit() grants access and ?cb_preview=1 is present.

What it is not

ContentBlocks is deliberately not a CMS. It has no admin panel, no user model, no routing, and no opinion about your CSS framework. It gives you a content-editing capability you embed into an app you already own.

• It does not own your URLs or SEO.
• It does not ship authentication — you wire your auth model through a thin AccessCheckerInterface.
• It does not force Tailwind, Bootstrap, or any icon library on you — the kit renders neutral markup styled by CSS custom properties.
• It does not take over your templates — you decide the final markup and can override every render template.

Vision

The goal is a page builder that feels like a native part of a Symfony application rather than a platform you migrate into:

• Framework-native. Doctrine entities, Symfony forms, Live Components, Stimulus. No bespoke runtime, no proprietary storage.
• Extensible before it is featureful. A block is one class + one form. The block-type system, the styling sub-form, the defaults providers and the decorators are all extension points, not walls.
• Host-owned, not tool-owned. Your entity, your URL, your auth, your markup. ContentBlocks fills exactly one gap — structured, editable content — and gets out of the way.
• Secure and predictable by default. Deny-all access, CSRF everywhere, the form as the data whitelist. You opt into surface, never out of safety.

Where to next

• Quick start — from composer require to a rendered content area in five minutes.
• Installation — the full install, with and without Symfony Flex.
• Core concepts — the data model, the block-type system, and the Live Components + Stimulus split.
• Block Kit — the 17 shipped blocks, documented one by one.