HTML Tools

Preload Tag Builder

Build preload tags by resource type. The tool ensures the correct as attribute, optional crossorigin, type, and media values are included. Avoids common preload mistakes.

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What is Preload Tag Builder?

Preload tells the browser to fetch a resource early before it would normally be discovered. It speeds up loading for fonts, hero images, critical CSS, and scripts. The as attribute is required to tell the browser what type of resource to expect. Missing as or incorrect crossorigin are common mistakes.

Quick answer

Use preload to fetch critical resources -- such as hero images, fonts, or above-the-fold CSS -- before the parser discovers them. Only preload a few resources per page to avoid bandwidth contention.

Limitations

  • Preload requires the as attribute. Omitting it or using an incorrect value may cause the browser to fetch the resource twice.
  • Cross-origin preloaded resources such as fonts from a CDN must include the crossorigin attribute.
  • Excessive preloading delays other resources and can hurt performance instead of helping.

How to use this tool

  1. Select the resource type you need to preload: font, image, CSS, or script.
  2. Enter the URL or file path of the resource.
  3. The tool adds the correct as and crossorigin attributes for the selected type.
  4. Copy the link tag into the page head before other resource references.

What you can use it for

  • Preload a critical font file so text renders correctly on the first paint.
  • Preload a hero image to improve Largest Contentful Paint.
  • Preload a critical CSS file or JavaScript module for faster rendering.

Use cases

Practical examples

Example

Web font preloading

A page uses a custom web font. The preload tag with as='font' and crossorigin fetches it early, reducing the flash of invisible text.

Example

Hero image preloading for LCP

A landing page preloads the hero background image with as='image' to reduce Largest Contentful Paint timing by several hundred milliseconds.

Common mistakes

  • Preloading too many resources which wastes bandwidth.
  • Using preload without the required as attribute.
  • Adding preload for cross-origin fonts without crossorigin.

Verification

  1. Open Chrome DevTools Network panel and verify the preloaded resource appears early in the request waterfall with the correct Priority.
  2. Check the browser console for missing preload warnings such as 'The resource was already loaded and preload was not used'.

Comparison

preload vs prefetch vs modulepreload

Aspectpreloadprefetchmodulepreload
What it loadsResources needed for the current pageResources likely needed for the next navigationES module scripts for the current page
When the browser fetches itImmediately, at high priority during page loadDuring idle time after the current page finishes loadingImmediately at high priority, similar to preload, but fetches the module and its dependencies
What it is best forCritical fonts, hero images, above-the-fold CSSNext-page resources such as docs, images, or scripts for the likely next pageES module entry points and their dependency trees in modern bundler output
Required attributesrel="preload" and the as attributerel="prefetch"rel="modulepreload"
Browser support milestoneChrome 50+, Safari 9+, Firefox 56+Chrome 50+, Safari 9+, Firefox 2+Chrome 80+, Safari 15+, Firefox 115+

Preload fetches current-page resources early at high priority. Prefetch fetches likely next-page resources during idle time. Modulepreload is a specialized preload for ES module scripts and their dependencies.

FAQ

Questions about Preload Tag Builder

What is the difference between preload and prefetch?

Preload fetches resources needed for the current page as early as possible. Prefetch fetches resources likely needed for the next navigation.

Should I preload everything?

No. Preload a small number of truly critical resources. Too many preload hints delay important resources.

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