Asset Preloading

The preload() method prepares the SDK in the background so it is ready before your user starts a liveness or identity verification flow.

Availability: preload() is available from SDK v1.1.3 onwards. Make sure your integration uses v1.1.3 or later before calling it.

Overview

When the SDK starts a verification flow, it needs to download several assets (see What gets prefetched). If these are downloaded only when the flow begins, the user may see a short loading delay.

preload() fetches these assets ahead of time and stores them in the browser cache. When the user later reaches the verification screen and your app calls init(), the assets are already available, so the flow starts faster.

When To Use

Call preload() on any page your user visits before the verification screen - for example a landing page, a consent screen, or a KYC introduction page.

By the time the user reaches the verification flow, the required assets will already be cached in the browser.

preload() is a new, optional method. It does not change your existing integration - init(), destroy(), and all other SDK methods work exactly as before. You can adopt preload() on its own, at any time.

Method Reference

VidaSDK.preload();

Property	Value
Parameters	None
Returns	void
Auth required	No - can be called without a token or signing key

Usage

CDN

<script src="https://web-sdk.vida.id/<VERSION>/vida-web-sdk.js"></script>
<script>
  VidaSDK.preload();
</script>

Replace <VERSION> with the SDK version you are using (v1.1.3 or later).

NPM

import { VidaSDK } from 'vida-web-sdk';

VidaSDK.preload();

What Gets Prefetched

Asset	Description
WASM binary	Vision runtime. The correct variant for the user's device is selected automatically.
JS glue file	JavaScript loader that starts the WASM binary.
Face detection model	Machine learning model used for face detection and landmark extraction.

Behaviour Notes

• Optional. If you do not call preload(), the SDK downloads its assets on demand when the verification flow starts. Everything still works — the flow may just take slightly longer to appear.

• Safe to call multiple times. Calling preload() more than once does not create duplicate downloads.

• Non-blocking. Assets are fetched using <link rel="prefetch">, which loads at low priority and does not slow down or block your page.