---
title: "Synchronizing PDF annotations on iOS | Nutrient"
canonical_url: "https://www.nutrient.io/guides/ios/annotations/synchronization/"
md_url: "https://www.nutrient.io/guides/ios/annotations/synchronization.md"
last_updated: "2026-06-09T07:58:07.177Z"
description: "Unlock the secrets of iOS annotation synchronization with our comprehensive guide. Learn how to optimize your workflow effortlessly. Click now!"
---

# Synchronizing PDF annotations on iOS

Nutrient iOS SDK supports two approaches for synchronizing annotations to your server, and across multiple users, devices, or sessions:

1. Instant synchronization

2. Building your own solution using our APIs

Both approaches are deployed on your infrastructure and can be integrated with our web, mobile, and desktop SDKs.

|                         | Instant synchronization     | Building your own |
| ----------------------- | --------------------------- | ----------------- |
| Backend                 | [Document Engine](https://www.nutrient.io/guides/document-engine.md)         | Any               |
| Real-time sync          | Built in                    | Not built in      |
| Conflict resolution     | Built in                    | Not built in      |
| User authentication     | [Built in](https://www.nutrient.io/guides/ios/instant-synchronization/authentication.md)    | Not built in      |
| Offline synchronization | [Built in](https://www.nutrient.io/guides/ios/pspdfkit-instant/offline-support.md) | Not built in      |
| Incremental sync        | Built in                    | Not built in      |

## Instant synchronization

[Instant](https://www.nutrient.io/guides/ios/instant-synchronization.md) is our prebuilt solution for synchronizing annotations to your server, and across multiple concurrent users, devices, or sessions. It’s a licensable component that’s included as part of [Document Engine](https://www.nutrient.io/guides/document-engine.md).

[Try for Free](https://www.nutrient.io/try)

[Launch Demo](https://www.nutrient.io/demo/instant-collaboration)

Instant consists of three parts: the Document Engine backend that synchronizes documents and annotations and manages authentication; the Nutrient Instant component that handles conflict resolution, version tracking, diffing, and merging; and the web, mobile, and desktop SDKs that integrate into your app.

Learn more about [Nutrient Instant](https://www.nutrient.io/guides/ios/instant-synchronization.md).

## Building your own solution

Nutrient web, mobile, and desktop SDKs have easy-to-use APIs for importing/exporting annotations and forms data as part of a robust synchronization solution.

Before starting, take a quick look at the following guides:

- [Storing annotation data](https://www.nutrient.io/guides/ios/annotations/synchronization/storing-annotation-data.md)

- [Conflict resolution](https://www.nutrient.io/guides/ios/annotations/synchronization/conflict-resolution.md)

- [Instant JSON overview](https://www.nutrient.io/guides/ios/json.md)

- [Event listeners](https://www.nutrient.io/guides/ios/events-and-notifications.md)

> **ℹ Info:** When building your own solution, our technical support team will gladly help with questions specific to using our SDK. However, due to the complexity of building your own synchronization solution, support is limited to Nutrient technology.
---

## Related pages

- [Resolve conflicts for concurrent editing on iOS](/guides/ios/annotations/synchronization/conflict-resolution.md)
- [Storing PDF annotation data on iOS](/guides/ios/annotations/synchronization/storing-annotation-data.md)