> ## Documentation Index
> Fetch the complete documentation index at: https://docs.powersync.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Capacitor SDK (alpha)
> Use PowerSync in Capacitor apps.
This SDK is distributed via NPM
Refer to `packages/capacitor` in the `powersync-js` repo on GitHub
Full API reference for the SDK
Gallery of example projects/demo apps built with Capacitor and PowerSync
Changelog for the SDK
This SDK is currently in an [**alpha** release](/resources/feature-status).
The SDK is largely built on our stable [Web SDK](/client-sdks/reference/javascript-web), so that functionality can be considered stable. However, the [Capacitor Community SQLite](https://github.com/capacitor-community/sqlite) integration for mobile platforms is in alpha for real-world testing and feedback. There are [known limitations](#limitations) currently.
**Built on the Web SDK**
The PowerSync Capacitor SDK is built on top of the [PowerSync Web SDK](/client-sdks/reference/javascript-web). 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](#limitations) below for details
All code examples from the Web SDK apply to Capacitor — use `@powersync/web` for imports instead of `@powersync/capacitor`. See the [JavaScript Web SDK reference](/client-sdks/reference/javascript-web) 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](https://www.npmjs.com/package/@powersync/capacitor) to your project:
```bash theme={null}
npm install @powersync/capacitor
```
```bash theme={null}
yarn add @powersync/capacitor
```
```bash theme={null}
pnpm install @powersync/capacitor
```
**Install Peer Dependencies**
You must also install the following peer dependencies:
```bash theme={null}
npm install @capacitor-community/sqlite @powersync/web @journeyapps/wa-sqlite
```
```bash theme={null}
yarn add @capacitor-community/sqlite @powersync/web @journeyapps/wa-sqlite
```
```bash theme={null}
pnpm install @capacitor-community/sqlite @powersync/web @journeyapps/wa-sqlite
```
After installing, sync your Capacitor project:
```bash theme={null}
npx cap sync
```
## 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 Streams (or legacy Sync Rules) (steps 1-4 in the [Setup Guide](/intro/setup-guide)).
### 1. Define the Client-Side Schema
This refers to the schema 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) — no migrations are required.
**Generate schema automatically**
In the [PowerSync Dashboard](https://dashboard.powersync.com/), select your project and instance and click the **Connect** button in the top bar to generate the client-side schema in your preferred language. The schema will be generated based off your Sync Streams/Rules.
Similar functionality exists in the [CLI](/tools/cli).
**Note:** The generated schema will not include an `id` column, as the client SDK automatically creates an `id` column of type `text`. Consequently, it is not necessary to specify an `id` column in your schema. For additional information on IDs, refer to [Client ID](/sync/advanced/client-id).
The types available are `text`, `integer` and `real`. These should map directly to the values produced by your [Sync Streams](/sync/streams/overview) (or legacy [Sync Rules](/sync/rules/overview)). 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](/sync/types).
**Example**:
**Note on imports**: While you install `@powersync/capacitor`, the Capacitor SDK extends the Web SDK so you import general components from `@powersync/web` (installed as a peer dependency). See the [JavaScript Web SDK schema definition section](/client-sdks/reference/javascript-web#1-define-the-client-side-schema) for more advanced examples.
```js theme={null}
// AppSchema.ts
import { column, Schema, Table } from '@powersync/web';
const lists = new Table({
created_at: column.text,
name: column.text,
owner_id: column.text
});
const todos = new Table(
{
list_id: column.text,
created_at: column.text,
completed_at: column.text,
description: column.text,
created_by: column.text,
completed_by: column.text,
completed: column.integer
},
{ indexes: { list: ['list_id'] } }
);
export const AppSchema = new Schema({
todos,
lists
});
// For types
export type Database = (typeof AppSchema)['types'];
export type TodoRecord = Database['todos'];
// OR:
// export type Todo = RowType;
export type ListRecord = Database['lists'];
```
**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 Streams](/sync/streams/overview) (or legacy [Sync Rules](/sync/rules/overview)). In your client-side app, you can read from and write to the local SQLite database, whether the user is online or offline.
**Example**:
The Capacitor PowerSyncDatabase automatically detects the platform and uses the appropriate database drivers:
* **Android and iOS**: Uses [Capacitor Community SQLite](https://github.com/capacitor-community/sqlite) for native database access
* **Web**: Falls back to the PowerSync Web SDK
```js theme={null}
import { PowerSyncDatabase } from '@powersync/capacitor';
// Import general components from the Web SDK package
import { Schema } from '@powersync/web';
import { Connector } from './Connector';
import { AppSchema } from './AppSchema';
/**
* The Capacitor PowerSyncDatabase will automatically detect the platform
* and use the appropriate database drivers.
*/
export const db = new PowerSyncDatabase({
// The schema you defined in the previous step
schema: AppSchema,
database: {
// Filename for the SQLite database — it's important to only instantiate one instance per file.
dbFilename: 'powersync.db'
}
});
```
When using custom database factories, be sure to specify the `CapacitorSQLiteOpenFactory` for Capacitor platforms:
```js theme={null}
import { PowerSyncDatabase } from '@powersync/capacitor';
import { WASQLiteOpenFactory, CapacitorSQLiteOpenFactory } from '@powersync/capacitor';
import { Schema } from '@powersync/web';
const db = new PowerSyncDatabase({
schema: AppSchema,
database: isWeb
? new WASQLiteOpenFactory({ dbFilename: "mydb.sqlite" })
: new CapacitorSQLiteOpenFactory({ dbFilename: "mydb.sqlite" })
});
```
Once you've instantiated your PowerSync database, call the [connect()](https://powersync-ja.github.io/powersync-js/web-sdk/classes/AbstractPowerSyncDatabase#connect) method to sync data with your backend.
**Note**: This section assumes you want to use PowerSync to sync your backend source database with SQLite in your app. If you only want to use PowerSync to manage your local SQLite database without sync, instantiate the PowerSync database without calling `connect()` and refer to our [Local-Only](/client-sdks/advanced/local-only-usage) guide.
```js theme={null}
export const setupPowerSync = async () => {
// Uses the backend connector that will be created in the next section
const connector = new Connector();
db.connect(connector);
};
```
### 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:
1. Retrieve an auth token to connect to the PowerSync instance.
2. 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.
Accordingly, the connector must implement two methods:
1. [PowerSyncBackendConnector.fetchCredentials](https://github.com/powersync-ja/powersync-js/blob/ed5bb49b5a1dc579050304fab847feb8d09b45c7/packages/common/src/client/connection/PowerSyncBackendConnector.ts#L16) - This method is automatically invoked by the PowerSync Client SDK to obtain authentication credentials. The SDK caches credentials internally and only calls this method when needed (e.g. on initial connection or when the token is near expiry). See [When `fetchCredentials()` is Called](/configuration/app-backend/client-side-integration#when-fetchcredentials-is-called) for details, and [Authentication Setup](/configuration/auth/overview) for instructions on how the credentials should be generated.
2. [PowerSyncBackendConnector.uploadData](https://github.com/powersync-ja/powersync-js/blob/ed5bb49b5a1dc579050304fab847feb8d09b45c7/packages/common/src/client/connection/PowerSyncBackendConnector.ts#L24) - This method will be automatically invoked by the PowerSync Client SDK whenever it needs to upload client-side writes to your app's backend API. You need to implement how those writes are processed and uploaded in this method. See [When `uploadData()` is Called](/configuration/app-backend/client-side-integration#when-uploaddata-is-called) for details on triggers, throttling, and retry behavior, and [Writing Client Changes](/handling-writes/writing-client-changes) for considerations on the app backend implementation.
**Example**:
See the [JavaScript Web SDK backend integration section](/client-sdks/reference/javascript-web#3-integrate-with-your-backend) for connector examples with Supabase and Firebase authentication, and handling `uploadData` with batch operations.
```js theme={null}
import { UpdateType } from '@powersync/web';
export class Connector {
async fetchCredentials() {
// Implement fetchCredentials to obtain a JWT from your authentication service.
// See https://docs.powersync.com/configuration/auth/overview
return {
endpoint: '[Your PowerSync instance URL or self-hosted endpoint]',
// Use a development token (see Authentication Setup https://docs.powersync.com/configuration/auth/development-tokens) to get up and running quickly
token: 'An authentication token'
};
}
async uploadData(database) {
// Implement uploadData to send local changes to your backend service.
// You can omit this method if you only want to sync data from the database to the client
// See example implementation here: https://docs.powersync.com/client-sdks/reference/javascript-web#3-integrate-with-your-backend
}
}
```
## Using PowerSync: CRUD functions
Once the PowerSync instance is configured you can start using the SQLite DB functions.
**All CRUD examples from the JavaScript Web SDK apply**: The Capacitor SDK uses the same API as the Web SDK. See the [JavaScript Web SDK CRUD functions section](/client-sdks/reference/javascript-web#using-powersync-crud-functions) for examples of `get`, `getAll`, `watch`, `execute`, `writeTransaction`, incremental watch updates, and differential results.
The most commonly used CRUD functions to interact with your SQLite data are:
* [PowerSyncDatabase.get](/client-sdks/reference/javascript-web#fetching-a-single-item) - get (SELECT) a single row from a table.
* [PowerSyncDatabase.getAll](/client-sdks/reference/javascript-web#querying-items-powersync.getall) - get (SELECT) a set of rows from a table.
* [PowerSyncDatabase.watch](/client-sdks/reference/javascript-web#watching-queries-powersync.watch) - execute a read query every time source tables are modified.
* [PowerSyncDatabase.execute](/client-sdks/reference/javascript-web#mutations-powersync.execute) - execute a write (INSERT/UPDATE/DELETE) query.
### Fetching a Single Item
The [get](https://powersync-ja.github.io/powersync-js/web-sdk/classes/PowerSyncDatabase#get) method executes a read-only (SELECT) query and returns a single result. It throws an exception if no result is found. Use [getOptional](https://powersync-ja.github.io/powersync-js/web-sdk/classes/PowerSyncDatabase#getoptional) to return a single optional result (returns `null` if no result is found).
```js theme={null}
// Find a list item by ID
export const findList = async (id) => {
const result = await db.get('SELECT * FROM lists WHERE id = ?', [id]);
return result;
}
```
### Querying Items (PowerSync.getAll)
The [getAll](https://powersync-ja.github.io/powersync-js/web-sdk/classes/PowerSyncDatabase#getall) method returns a set of rows from a table.
```js theme={null}
// Get all list IDs
export const getLists = async () => {
const results = await db.getAll('SELECT * FROM lists');
return results;
}
```
### Watching Queries (PowerSync.watch)
The [watch](https://powersync-ja.github.io/powersync-js/web-sdk/classes/PowerSyncDatabase#watch) method executes a read query whenever a change to a dependent table is made.
```javascript theme={null}
async function* pendingLists(): AsyncIterable {
for await (const result of db.watch(
`SELECT * FROM lists WHERE state = ?`,
['pending']
)) {
yield result.rows?._array ?? [];
}
}
```
```javascript theme={null}
const pendingLists = (onResult: (lists: any[]) => void): void => {
db.watch(
'SELECT * FROM lists WHERE state = ?',
['pending'],
{
onResult: (result: any) => {
onResult(result.rows?._array ?? []);
}
}
);
}
```
For advanced watch query features like incremental updates and differential results, see [Live Queries / Watch Queries](/client-sdks/watch-queries).
### Mutations (PowerSync.execute, PowerSync.writeTransaction)
The [execute](https://powersync-ja.github.io/powersync-js/web-sdk/classes/PowerSyncDatabase#execute) method can be used for executing single SQLite write statements.
```js theme={null}
// Delete a list item by ID
export const deleteList = async (id) => {
const result = await db.execute('DELETE FROM lists WHERE id = ?', [id]);
return TodoList.fromRow(results);
}
// OR: using a transaction
const deleteList = async (id) => {
await db.writeTransaction(async (tx) => {
// Delete associated todos
await tx.execute(`DELETE FROM ${TODOS_TABLE} WHERE list_id = ?`, [id]);
// Delete list record
await tx.execute(`DELETE FROM ${LISTS_TABLE} WHERE id = ?`, [id]);
});
};
```
When using the default client-side [JSON-based view system](/architecture/client-architecture#client-side-schema-and-sqlite-database-structure), writes are applied to a view, with triggers writing to the underlying table. Because of this, `result.rowsAffected` from `db.execute()` can be `0` even when an `UPDATE` or `DELETE` succeeds.
When you need to confirm whether a mutation changed any rows, add a `RETURNING` clause and check the returned rows:
```js theme={null}
const result = await db.execute(
'UPDATE tasks SET deleted_at = ? WHERE id = ? AND deleted_at IS NULL RETURNING id',
[now, id]
);
const wasUpdated = (result.rows?.length ?? 0) > 0;
```
If you need direct table writes, use [raw tables](/client-sdks/advanced/raw-tables).
## Configure Logging
```js theme={null}
import { createBaseLogger, LogLevel } from '@powersync/web';
const logger = createBaseLogger();
// Configure the logger to use the default console output
logger.useDefaults();
// Set the minimum log level to DEBUG to see all log messages
// Available levels: DEBUG, INFO, WARN, ERROR, TRACE, OFF
logger.setLevel(LogLevel.DEBUG);
```
Enable verbose output in the developer tools for detailed logs.
## Limitations
* Encryption for native mobile platforms is not yet supported.
* Multiple tab support is not available for native Android and iOS targets.
* `PowerSyncDatabase.executeRaw` does not support results where multiple columns would have the same name in SQLite
* `PowerSyncDatabase.execute` has 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](/client-sdks/usage-examples) page.
## ORM Support
See [JavaScript ORM Support](/client-sdks/orms/js/overview) for details.
## Troubleshooting
See [Troubleshooting](/debugging/troubleshooting) for pointers to debug common issues.
## Supported Platforms
See [Supported Platforms -> Capacitor SDK](/resources/supported-platforms#capacitor-sdk).
## Upgrading the SDK
Run the below command in your project folder:
```bash theme={null}
npm upgrade @powersync/capacitor @powersync/web
```
```bash theme={null}
yarn upgrade @powersync/capacitor @powersync/web
```
```bash theme={null}
pnpm upgrade @powersync/capacitor @powersync/web
```