> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pocketsync.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Offline capabilities

> Strategies and best practices for building offline-first applications with PocketSync

## Understanding offline-first

Offline-first is an approach to application development that prioritizes the offline experience, ensuring your app works seamlessly regardless of network connectivity. PocketSync is built with offline-first principles at its core.

### Key Principles

<CardGroup cols={2}>
  <Card title="Local-First Data" icon="database">
    Store all essential data locally and treat the local database as the primary source of truth.
  </Card>

  <Card title="Optimistic UI Updates" icon="bolt">
    Apply UI changes immediately without waiting for server confirmation, then reconcile later.
  </Card>

  <Card title="Background Synchronization" icon="arrows-rotate">
    Sync data in the background when connectivity is restored without user intervention.
  </Card>

  <Card title="Conflict Resolution" icon="code-merge">
    Handle conflicts that arise when the same data is modified in different offline states.
  </Card>
</CardGroup>

## Testing offline capabilities

### Manual testing

1. **Airplane mode test**: Toggle airplane mode on and off to simulate connectivity changes and verify data syncs when connection is restored
2. **Slow network test**: Use network throttling tools to simulate poor connectivity and ensure the app remains responsive
3. **Extended offline test**: Keep the app offline for several days, make multiple changes, then reconnect to verify all changes synchronize properly

## Best practices

Building offline-first applications with PocketSync enables your users to have a seamless experience regardless of network conditions. By implementing these best practices, you can create applications that are resilient, responsive, and user-friendly:

1. **Design for offline first**: Assume users will frequently be offline and design your app's workflow accordingly
2. **Implement optimistic UI**: Update the interface immediately without waiting for server confirmation
3. **Handle conflicts intelligently**: Choose appropriate conflict resolution strategies for different data types
4. **Test thoroughly**: Simulate various network conditions to ensure your app functions reliably in all scenarios

<Card title="Learn more about conflict resolution" icon="code-merge" href="/core-concepts/conflict-resolution">
  Dive deeper into how PocketSync handles data conflicts
</Card>