---
title: "Nutrient Instant usage on iOS"
canonical_url: "https://www.nutrient.io/guides/ios/pspdfkit-instant/usage/"
md_url: "https://www.nutrient.io/guides/ios/pspdfkit-instant/usage.md"
last_updated: "2026-06-09T10:38:40.897Z"
description: "Instant usage on iOS guide for Nutrient iOS SDK with detailed instructions and code examples."
---

# Nutrient Instant usage

The entry class into Instant is [`InstantClient`](https://www.nutrient.io/api/ios/documentation/instant/instantclient). This represents a connection to your Document Engine. An app typically creates one [`InstantClient`](https://www.nutrient.io/api/ios/documentation/instant/instantclient), although it could create several to connect to multiple Document Engine instances.

Instant manages downloading and storing PDF files when your app requests this. Each PDF file managed by Instant is identified by its [`identifier`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor/identifier) and can have one or more named [layers](https://www.nutrient.io/../instant-layers). Each layer represents a separate set of annotations displayed on top of the base file and is uniquely identified by the combination of [`identifier`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor/identifier) and [`layerName`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor/layername).

The API to each layer managed by Instant is [`InstantDocumentDescriptor`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor). A document descriptor may be used to request downloading the associated PDF file and annotations by calling [`download(usingJWT:)`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor/download(usingjwt:)) with an appropriate [JSON Web Token (JWT)](https://www.nutrient.io/guides/document-engine/viewer/client-authentication.md). It can also be used to create a [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document). Set this document on an [`InstantViewController`](https://www.nutrient.io/api/ios/documentation/instant/instantviewcontroller) and then show it to the user. The view controller will show a download progress bar and then refresh to display the PDF when the download completes. Changes to annotations in the [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document) will be seen by all users viewing the same layer.

[`InstantViewController`](https://www.nutrient.io/api/ios/documentation/instant/instantviewcontroller) is a subclass of [`PDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller) and may be used to show any [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document) — not just those created by Instant. However, there won’t be any annotation synchronization for documents that weren’t created by Instant. This means it’s possible to create a [`PDFTabbedViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdftabbedviewcontroller) whose internal [`pdfController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/multidocumentviewcontroller/pdfcontroller) is an [`InstantViewController`](https://www.nutrient.io/api/ios/documentation/instant/instantviewcontroller). You can also mix documents managed by Instant with other documents in the tabbed bar. Showing a [`Document`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document) created by an [`InstantDocumentDescriptor`](https://www.nutrient.io/api/ios/documentation/instant/instantdocumentdescriptor) in any [`PDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller) except an [`InstantViewController`](https://www.nutrient.io/api/ios/documentation/instant/instantviewcontroller) isn’t supported.
---

## Related pages

- [Streamline PDF annotation syncing on iOS](/guides/ios/pspdfkit-instant/syncing.md)
- [Nutrient Instant and iOS data protection](/guides/ios/pspdfkit-instant/data-protection.md)
- [Adding comments to PDFs on iOS](/guides/ios/comments/introduction-to-instant-comments.md)
- [Client authentication in Nutrient Instant](/guides/ios/instant-synchronization/authentication.md)
- [Frequently asked questions](/guides/ios/instant-synchronization/faq.md)
- [Nutrient Instant and the document state](/guides/ios/pspdfkit-instant/instant-document-state.md)
- [PDF collaboration library for iOS](/guides/ios/instant-synchronization.md)
- [Integrating real-time collaboration into your iOS application](/guides/ios/pspdfkit-instant/getting-started.md)
- [Seamless offline PDF annotation and synchronization](/guides/ios/pspdfkit-instant/offline-support.md)
- [Create PDF annotation layers on iOS](/guides/ios/pspdfkit-instant/instant-layers.md)