> ## Documentation Index
> Fetch the complete documentation index at: https://powersync-sync-streams-nav.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Capacitor SDK (beta)
> Use PowerSync in Capacitor apps.
```text Build with AI icon="sparkles" wrap theme={null}
Install the PowerSync Agent Skills with: npx skills add powersync-ja/agent-skills. Then follow the skills to onboard this project to PowerSync using the Capacitor SDK.
```
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 a [**beta** release](/resources/feature-status).
Because the SDK is largely built on our [Web SDK](/client-sdks/reference/javascript-web), much of its functionality is stable. The portion that relies on the [Capacitor Community SQLite](https://github.com/capacitor-community/sqlite) driver is considered production-ready for tested use cases. Review the [known limitations](#limitations) below.
**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:
* It uses the Capacitor-specific SQLite implementation (`@capacitor-community/sqlite`) on native Android and iOS.
* Some features are not supported on native Android and iOS. See [Limitations](#limitations).
All code examples from the Web SDK apply to Capacitor. Import general components such as `Schema` and `Table` from `@powersync/web`, and `PowerSyncDatabase` from `@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 handle schema changes without explicit migrations on the client side.
## Installation
**Requirements**: The Capacitor SDK requires Capacitor 8 or later. Minimum platform versions are iOS 15.0 and Android API level 24. On iOS, both Swift Package Manager (SPM) and CocoaPods are supported.
If you are on Capacitor 6 or 7, follow the [Capacitor v8 upgrade guide](https://capacitorjs.com/docs/updating/8-0) before installing or upgrading `@powersync/capacitor`.
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
```
```bash theme={null}
yarn add @capacitor-community/sqlite @powersync/web
```
```bash theme={null}
pnpm install @capacitor-community/sqlite @powersync/web
```
After installing, sync your Capacitor project:
```bash theme={null}
npx cap sync
```
## Getting Started
**Prerequisites:** Before you start, connect your source database to the PowerSync Service and deploy Sync Streams. These are steps 1-4 in the [Setup Guide](/intro/setup-guide).
### 1. Define the Client-Side Schema
The client-side schema defines the tables and columns of the SQLite database that the PowerSync client SDK manages and that your app reads from and writes to. It is usually derived from your backend database schema and your [Sync Streams](/sync/streams/overview), and it can also include [local-only tables](/client-sdks/advanced/local-only-usage). You apply the schema when you instantiate the database in the next step.
Schema migrations are not required. The SDK syncs schemaless data and applies the schema to that data with SQLite views. The exception is [raw tables](/client-sdks/advanced/raw-tables), which you create and migrate yourself.
**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 is generated from your Sync Streams. The [CLI](/tools/cli) offers the same function.
The generated schema does not include an `id` column. The client SDK creates an `id` column of type `text` automatically, so you do not need to declare it. See [Client ID](/sync/advanced/client-id) for details.
The available column types are `text`, `integer`, and `real`. These should match the values produced by your Sync Streams. If a value does not match, it is cast automatically. For details on how source database types map to SQLite types, see [Types](/sync/types).
**Example:**
**Imports:** You install `@powersync/capacitor`, but 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'];
```
You do not need to declare an `id` column. PowerSync creates it automatically.
### 2. Instantiate the PowerSync Database
Next, instantiate the PowerSync database. PowerSync streams changes from your backend source database into the client-side SQLite database, based on your Sync Streams. Your app reads from and writes to this local database whether the user is online or offline.
**Example:**
The Capacitor `PowerSyncDatabase` detects the platform and uses the matching database driver:
* **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 you use custom database factories, specify `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,
factory: isWeb
? new WASQLiteOpenFactory({ dbFilename: "mydb.sqlite" })
: new CapacitorSQLiteOpenFactory({ dbFilename: "mydb.sqlite" })
});
```
After you instantiate the PowerSync database, call the [connect()](https://powersync-ja.github.io/powersync-js/common/interfaces/CommonPowerSyncDatabase#connect) method to sync data with your backend.
This section assumes that you use PowerSync to sync your backend source database with SQLite in your app. To manage a local SQLite database without sync, instantiate the PowerSync database without calling `connect()` and see the [Local-Only](/client-sdks/advanced/local-only-usage) guide.
```js theme={null}
export const setupPowerSync = async () => {
// Uses the backend connector that you create in the next step
const connector = new Connector();
db.connect(connector);
};
```
### 3. Integrate with Your Backend
The backend connector connects the PowerSync client SDK to your application backend. The SDK uses it to:
1. Get an auth token to connect to the PowerSync instance.
2. Upload client-side writes to your backend API. The SDK places every write to the SQLite database in an upload queue and uploads the queue to your backend when the user is connected. Your backend then applies the changes to the source database.
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) - The SDK calls this method to get authentication credentials. It caches the credentials and calls the method again only when needed, for example on the first 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 how to generate credentials.
2. [PowerSyncBackendConnector.uploadData](https://github.com/powersync-ja/powersync-js/blob/ed5bb49b5a1dc579050304fab847feb8d09b45c7/packages/common/src/client/connection/PowerSyncBackendConnector.ts#L24) - The SDK calls this method whenever it has client-side writes to upload to your backend API. Implement how those writes are processed and uploaded. See [When `uploadData()` is Called](/configuration/app-backend/client-side-integration#when-uploaddata-is-called) for triggers, throttling, and retry behavior, and [Writing Client Changes](/handling-writes/writing-client-changes) for 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/usage-examples#send-changes-in-local-data-to-your-backend-service
}
}
```
### 4. Subscribe to Sync Streams
Streams defined with `auto_subscribe: true` start syncing as soon as the client connects. For all other streams, your app must subscribe before their data downloads. The basic pattern is: subscribe to a stream, wait for its data to sync, then unsubscribe when the data is no longer needed.
```js theme={null}
// Subscribe to a stream with parameters
const sub = await db.syncStream('list_todos', { list_id: 'abc123' }).subscribe();
// Wait for the initial data to sync
await sub.waitForFirstSync();
// The stream's rows are now in the local SQLite database.
// TODO: Read the todos for this list with a local query.
// When the data is no longer needed
sub.unsubscribe();
```
After you unsubscribe, the synced data stays in the local database for the stream's time-to-live (TTL), which is 24 hours by default. If the app subscribes again within that time, the data is already available. See [Client-Side Usage](/sync/streams/client-usage) for framework hooks, per-subscription sync status, custom TTLs, priority overrides, and connection parameters.
## Using PowerSync: CRUD Functions
Once the PowerSync database is connected and your streams have synced, the data is in the local SQLite database.
**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 a dependent table changes.
* [PowerSyncDatabase.execute](/client-sdks/reference/javascript-web#mutations-powersync-execute-powersync-writetransaction) - execute a write (`INSERT`/`UPDATE`/`DELETE`) query.
### Fetching a Single Item
The [get](https://powersync-ja.github.io/powersync-js/common/interfaces/CommonPowerSyncDatabase#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/common/interfaces/CommonPowerSyncDatabase#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/common/interfaces/CommonPowerSyncDatabase#getall) method returns a set of rows from a table.
```js theme={null}
// Get all lists
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/common/interfaces/CommonPowerSyncDatabase#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 such as 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/common/interfaces/CommonPowerSyncDatabase#execute) method can be used for executing single SQLite write statements.
```js theme={null}
// Delete a list by ID
export const deleteList = async (id) => {
await db.execute('DELETE FROM lists WHERE id = ?', [id]);
};
// OR: delete the list and its todos in one transaction
export const deleteListWithTodos = async (id) => {
await db.writeTransaction(async (tx) => {
await tx.execute('DELETE FROM todos WHERE list_id = ?', [id]);
await tx.execute('DELETE FROM lists 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 { createConsoleLogger, LogLevels } from '@powersync/web';
// Create a logger with trace minimum level to see all log messages
// Available levels: trace, debug, info, warn, error
const logger = createConsoleLogger({ minLevel: LogLevels.trace });
```
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 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. On Android, the SDK treats 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).
## Upgrading the SDK
Run the following 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
```