PowerSync SDK on NPM
This SDK is distributed via NPM
Source Code
Refer to
packages/capacitor in the powersync-js repo on GitHubAPI Reference
Full API reference for the SDK
Example Projects
Gallery of example projects/demo apps built with Capacitor and PowerSync
Changelog
Changelog for the SDK
Built on the Web SDKThe PowerSync Capacitor SDK is built on top of the PowerSync Web SDK. It shares the same API and usage patterns as the Web SDK. The main differences are:
- Uses Capacitor-specific SQLite implementation (
@capacitor-community/sqlite) for native Android and iOS platforms - Certain features are not supported on native Android and iOS platforms, see limitations below for details
@powersync/web for imports instead of @powersync/capacitor. See the JavaScript Web SDK reference for ORM support, SPA framework integration, and developer notes.SDK Features
- Real-time streaming of database changes: Changes made by one user are instantly streamed to all other users with access to that data. This keeps clients automatically in sync without manual polling or refresh logic.
- Direct access to a local SQLite database: Data is stored locally, so apps can read and write instantly without network calls. This enables offline support and faster user interactions.
- Asynchronous background execution: The SDK performs database operations in the background to avoid blocking the application’s main thread. This means that apps stay responsive, even during heavy data activity.
- Query subscriptions for live updates: The SDK supports query subscriptions that automatically push real-time updates to client applications as data changes, keeping your UI reactive and up to date.
- Automatic schema management: PowerSync syncs schemaless data and applies a client-defined schema using SQLite views. This architecture means that PowerSync SDKs can handle schema changes gracefully without requiring explicit migrations on the client-side.
Installation
Add the PowerSync Capacitor NPM package to your project:- npm
- yarn
- pnpm
- npm
- yarn
- pnpm
Getting Started
Prerequisites: To sync data between your client-side app and your backend source database, you must have completed the necessary setup for PowerSync, which includes connecting your source database to the PowerSync Service and deploying Sync Rules (steps 1-4 in the Setup Guide).1. Define the Client-Side Schema
This refers to the for the managed SQLite database exposed by the PowerSync Client SDKs, that your app can read from and write to. The schema is applied when the database is instantiated (as we’ll show in the next step) — . The types available aretext, integer and real. These should map directly to the values produced by the Sync Rules. If a value doesn’t match, it is cast automatically. For details on how backend source database types are mapped to the SQLite types, see Types.
Example:
Note: No need to declare a primary key
id column, as PowerSync will automatically create this.2. Instantiate the PowerSync Database
Next, you need to instantiate the PowerSync database. PowerSync streams changes from your backend source database into the client-side SQLite database, based on your Sync Rules. In your client-side app, you can read from and write to the local SQLite database, whether the user is online or offline. Example:CapacitorSQLiteOpenFactory for Capacitor platforms:
3. Integrate with your Backend
The PowerSync backend connector provides the connection between your application backend and the PowerSync client-side managed SQLite database. It is used to:- Retrieve an auth token to connect to the PowerSync instance.
- Upload client-side writes to your backend API. Any writes that are made to the SQLite database are placed into an upload queue by the PowerSync Client SDK and automatically uploaded to your app backend (where you apply those changes to the backend source database) when the user is connected.
- PowerSyncBackendConnector.fetchCredentials - This method will be automatically invoked by the PowerSync Client SDK every couple of minutes to obtain authentication credentials. See Authentication Setup for instructions on how the credentials should be generated.
- PowerSyncBackendConnector.uploadData - This method will be automatically invoked by the PowerSync Client SDK whenever it needs to upload client-side writes to your app backend via your backend API. Therefore, in your implememtation, you need to define how your backend API is called. See Writing Client Changes for considerations on the app backend implementation.
Using PowerSync: CRUD functions
Once the PowerSync instance is configured you can start using the SQLite DB functions. The most commonly used CRUD functions to interact with your SQLite data are:- PowerSyncDatabase.get - get (SELECT) a single row from a table.
- PowerSyncDatabase.getAll - get (SELECT) a set of rows from a table.
- PowerSyncDatabase.watch - execute a read query every time source tables are modified.
- PowerSyncDatabase.execute - execute a write (INSERT/UPDATE/DELETE) query.
Fetching a Single Item
The get method executes a read-only (SELECT) query and returns a single result. It throws an exception if no result is found. Use getOptional to return a single optional result (returnsnull if no result is found).
Querying Items (PowerSync.getAll)
The getAll method returns a set of rows from a table.Watching Queries (PowerSync.watch)
The watch method executes a read query whenever a change to a dependent table is made.- AsyncIterator approach
- Callback approach
Mutations (PowerSync.execute, PowerSync.writeTransaction)
The execute method can be used for executing single SQLite write statements.Configure Logging
Limitations
- Encryption for native mobile platforms is not yet supported.
- Multiple tab support is not available for native Android and iOS targets.
PowerSyncDatabase.executeRawdoes not support results where multiple columns would have the same name in SQLitePowerSyncDatabase.executehas limited support on Android. The SQLCipher Android driver exposes queries and executions as separate APIs, so there is no single method that handles both. While PowerSyncDatabase.execute accepts both, on Android we treat a statement as a query only when the SQL starts with select (case-insensitive).
Additional Usage Examples
For more usage examples including accessing connection status, monitoring sync progress, and waiting for initial sync, see the Usage Examples page.ORM Support
See JavaScript ORM Support for details.Troubleshooting
See Troubleshooting for pointers to debug common issues.Supported Platforms
See Supported Platforms -> Capacitor SDK.Upgrading the SDK
Run the below command in your project folder:- npm
- yarn
- pnpm