---
title: "Instant sync & document state in Flutter | Nutrient SDK"
canonical_url: "https://www.nutrient.io/guides/flutter/instant-synchronization/document-state/"
md_url: "https://www.nutrient.io/guides/flutter/instant-synchronization/document-state.md"
last_updated: "2026-05-20T19:49:34.815Z"
description: "Learn how to manage document states in Flutter with Nutrient Instant. Handle sync operations, authentication, and download events effectively for seamless integration."
---

# Instant sync and document state in Flutter

Over the course of its lifetime, any Instant document will go through several states. Nutrient Instant for Flutter provides a number of callbacks from the Instant document state, outlined below:

- `onSyncStarted` — Triggered when a sync operation starts. This can be a sync initiated by the user or a sync triggered automatically by the Instant document.

- `onSyncFinished` — Triggered when a sync operation completes successfully.

- `instantSyncFailed` — Triggered when a sync operation fails. It includes an error message explaining the cause of the failure.

- `instantAuthenticationFinished` — Triggered when the user successfully completes the authentication process for the Instant document.

- `instantAuthenticationFailed` — Triggered when the user fails to authenticate for the Instant document. It includes an error message explaining the cause of the failure.

- `instantDownloadFinished` (iOS only) — Triggered when a download operation for the Instant document completes successfully.

- `instantDownloadFailed` (iOS only) — Triggered when a download operation for the Instant document fails. It includes an error message explaining the cause of the failure.

For detailed guides about the Instant document state, refer to the [Android](https://www.nutrient.io/guides/android/pspdfkit-instant/instant-document-state.md) and [iOS](https://www.nutrient.io/guides/ios/pspdfkit-instant/instant-document-state.md) guides.
---

## Related pages

- [Client authentication in Nutrient Instant](/guides/flutter/instant-synchronization/authentication.md)
- [Sync PDF annotations in Flutter apps](/guides/flutter/instant-synchronization/annotation-sync.md)
- [Adding Instant comments to PDFs in Flutter](/guides/flutter/instant-synchronization/comments.md)
- [Integrating real-time collaboration into your Flutter application](/guides/flutter/instant-synchronization/get-started.md)
- [PDF collaboration library for Flutter](/guides/flutter/instant-synchronization.md)
- [NutrientInstantView widget](/guides/flutter/instant-synchronization/instant-view.md)
- [Offline PDF annotations with automatic sync](/guides/flutter/instant-synchronization/offline-support.md)
- [Create PDF annotation layers in Flutter](/guides/flutter/instant-synchronization/instant-layers.md)
- [Nutrient Instant usage](/guides/flutter/instant-synchronization/usage.md)