Building a Page Builder Model: Sections, Blocks, and Guardrails

A page builder in a CMS lets editors compose pages from sections and blocks. Designing the model and guardrails keeps both the editor experience and the front end maintainable.

Sections and blocks

Sections are top-level chunks of a page (e.g. hero, features, CTA, footer). Each section has a type and the fields needed for that type. Blocks are smaller units that can live inside a section or in a list (e.g. feature card, testimonial, button). Model sections as a repeatable list (dynamic zone or repeatable component) so the page is an ordered sequence of section types. Keep the set of section types small (e.g. 5–12) so the UI is understandable and the front end has one component per type. Use blocks for reusable pieces so you don’t duplicate the same structure in many section types.

Field guardrails

Give editors clear options instead of free text where it makes sense: select or enum for “style” (e.g. light/dark), “layout” (e.g. two-column, stacked), or “size.” Use validation: required fields, max length, or allowed link types so content doesn’t break the layout. For media, require alt text for accessibility and optionally constrain dimensions or aspect ratio. Guardrails reduce invalid states and support consistent rendering on the front end.

Front-end mapping

Each section type maps to one React (or other) component. The front end receives the ordered list of sections, and for each item reads the type and fields and renders the matching component. Keep the mapping explicit: a registry or a switch that lists every section type so adding a new one is a single place to update. Validate or type the API response so mismatched or new types don’t silently render nothing or break the page.

const sectionComponents = {
  hero: HeroSection,
  features: FeaturesSection,
  cta: CTASection,
};
 
function PageBuilder({ sections }) {
  return (
    <>
      {sections.map((section) => {
        const Comp = sectionComponents[section.__typename ?? section.type];
        if (!Comp) return null;
        return <Comp key={section.id} {...section} />;
      })}
    </>
  );
}

Documentation and limits

Document which section and block types exist and when to use them. Optionally set limits (e.g. max 1 hero per page, max 10 items in a list) so pages don’t become unwieldy or slow. With a clear model, guardrails, and a single mapping layer, the page builder stays flexible for editors and maintainable for developers.

Summary

Model pages as an ordered list of section types; keep the set small and use blocks for reusable pieces. Add field guardrails (options, validation, required alt). Map each section type to one component and document types and limits. That’s a page builder model that scales without chaos.