# SDKInitOptions.subsetterUrl

Part of [Initialization](https://kernstra.com/docs/web-sdk/config/init) in the Kernstra Web SDK 1.0.0 configuration reference.

- Type: `string`
- Page: https://kernstra.com/docs/web-sdk/config/init/subsetterurl

A self-hosted copy of `pdf-subset.bin` (~0.6 MB), the font-subsetting binary — self-hosting licenses only, likewise refused with `FEATURE_NOT_LICENSED` without self-hosting. It is downloaded on first use when [`fonts.subset`](https://kernstra.com/docs/web-sdk/config/fonts/subset) is on, so an exported document embeds only the glyphs it uses. Fetch it once from the store under the `subsetter` folder by `Kernstra.assetDigests.subset`. It is optional: if it cannot be loaded, the SDK warns once in the console and embeds full fonts, as it does with subsetting off.

Web page: https://kernstra.com/docs/web-sdk/config/init/subsetterurl