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Build a Custom Block With the Interactivity API

Add front-end interactivity to a block without shipping a framework. A hands-on starter.

DP
Devon Price
June 8, 2026 · 2 min read
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Add front-end interactivity to a block without shipping a framework. A hands-on starter. In this tutorials piece we go past the headline and into what actually matters when you sit down to do the work on a real site.

Why this matters

The WordPress ecosystem moves fast, and it is easy to act on a change before understanding its trade-offs. We tested this on production-scale sites so you do not have to learn the hard way.

Always test major changes on a staging site first. A five-minute clone can save you hours of downtime.

How to get started

Start small and measure. The steps below cover the essentials without turning a quick task into an afternoon.

  • Back up the site (files and database) before you change anything.
  • Apply the change on staging and confirm nothing regresses.
  • Measure the before/after — load time, errors, and Core Web Vitals.

If you prefer to configure this in code, drop the snippet below into your theme’s functions.php:

add_action( 'after_setup_theme', function () {
    add_theme_support( 'block-bindings' );
} );

The bottom line

For most sites this is worth doing after a quick staging test. The wins are real, and the risk is manageable when you follow the steps above.

DP
Written by
Devon Price

Devon writes the step-by-step guides WPInsider is known for, from first install to advanced developer workflows.

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