> ## 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.
# Tauri SDK (alpha)
> Use PowerSync in Tauri 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 Tauri SDK.
```
The JavaScript part of the SDK is distributed via NPM
The Rust part of the SDK is available via crates.io
Refer to `packages/tauri` in the `powersync-js` repo on GitHub
Full API reference for the SDK
Gallery of example projects/demo apps built with Tauri and PowerSync
Changelog for the SDK
This SDK is currently in [**alpha**](/resources/feature-status), intended for external testing and public feedback. While it exposes the same stable JavaScript APIs as other PowerSync JavaScript SDKs, the underlying [Rust SDK](/client-sdks/reference/rust) and the IPC protocol between the JavaScript and Rust packages are subject to change. Expect breaking changes and instability as development continues.
There are [known limitations](#limitations) currently.
## 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
Add the [PowerSync Tauri NPM package](https://www.npmjs.com/package/@powersync/tauri-plugin) to your project:
```bash theme={null}
npm install @powersync/tauri-plugin
```
```bash theme={null}
yarn add @powersync/tauri-plugin
```
```bash theme={null}
pnpm install @powersync/tauri-plugin
```
Like all trusted PowerSync packages, the Tauri plugin is only available through the `@powersync/` scope on npm.
The PowerSync Tauri plugin **cannot** be installed with the `tauri add` command.
Additionally, add the Tauri plugin crate to your Rust app (in the `src-tauri` directory):
```bash theme={null}
cargo add tauri-plugin-powersync
```
In your `lib.rs`, ensure the plugin is loaded:
```diff theme={null}
pub fn run() {
tauri::Builder::default()
.invoke_handler(tauri::generate_handler![connect])
+ .plugin(tauri_plugin_powersync::init())
.run(tauri::generate_context!())
.expect("error while running tauri application");
}
```
In `src-tauri/capabilities/default.json`, ensure `powersync:default` is listed under `permissions` to make PowerSync APIs available to JavaScript.
## 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).
The Tauri SDK inherits the same APIs from the JavaScript Web SDK via `@powersync/common`, with a few exceptions detailed below. See the [Web SDK schema definition section](/client-sdks/reference/javascript-web#1-define-the-client-side-schema) for more advanced examples.
**Example:**
```js theme={null}
// AppSchema.ts
import { column, Schema, Table } from '@powersync/common';
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:**
```js theme={null}
import { PowerSyncTauriDatabase } from '@powersync/tauri-plugin';
import { appDataDir } from '@tauri-apps/api/path';
import { AppSchema } from './AppSchema';
export const db = new PowerSyncTauriDatabase({
// The schema you defined in the previous step
schema: AppSchema,
database: {
// Filename for the SQLite database.
dbFilename: 'powersync.db',
// An optional directory to store the database file in.
dbLocationAsync: appDataDir,
}
});
```
Finally, instruct PowerSync to sync data from your backend. For Tauri apps, the sync client
must be driven from Rust code.
To do that, add a new Tauri command to your Rust application:
```Rust theme={null}
use tauri_plugin_powersync::PowerSyncExt;
#[tauri::command]
async fn connect(
app: AppHandle,
handle: usize,
) -> tauri_plugin_powersync::Result<()> {
let ps = app.powersync();
let database = ps.database_from_javascript_handle(handle)?;
// MyBackendConnector is defined in the next step...
let options = SyncOptions::new(MyRustConnector {
db: database.clone(),
});
database.connect(options).await;
Ok(())
}
```
Register the command by including it in the invoke handler with
`tauri::generate_handler![connect]`.
You can then invoke that command from your JavaScript code to connect:
```TypeScript theme={null}
import { PowerSyncTauriDatabase } from '@powersync/tauri-plugin';
import { invoke } from '@tauri-apps/api/core';
async function connect(db: PowerSyncTauriDatabase) {
await db.init();
const handle = db.rustHandle;
await invoke('connect', { handle });
}
```
### 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.
At the moment, backend connectors for the Tauri SDK must be implemented in Rust.
This allows the connector to be used across multiple windows and even when no JavaScript is running.
[Let us know](/resources/contact-us) if you want to implement a backend connector in JavaScript.
The connector must implement two methods:
1. `fetch_credentials` - 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. `upload_data` - 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:**
```Rust theme={null}
struct MyBackendConnector {
db: PowerSyncDatabase,
}
#[async_trait]
impl BackendConnector for MyBackendConnector {
async fn fetch_credentials(&self) -> Result {
// implement fetchCredentials to obtain the necessary credentials to connect to your backend
// See an example implementation in https://github.com/powersync-ja/powersync-native/blob/508193b0822b8dad1a534a16462e2fcd36a9ac68/examples/egui_todolist/src/database.rs#L119-L133
Ok(PowerSyncCredentials {
endpoint: "[Your PowerSync instance URL or self-hosted endpoint]".to_string(),
// 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".to_string(),
})
}
async fn upload_data(&self) -> Result<(), PowerSyncError> {
// Implement uploadData to send local changes to your backend service
// You can omit this method if you only want to sync data from the server to the client
// See an example implementation under Usage Examples (sub-page)
// See https://docs.powersync.com/handling-writes/writing-client-changes for considerations.
let mut local_writes = self.db.crud_transactions();
while let Some(tx) = local_writes.try_next().await? {
todo!("Inspect tx.crud for local writes that need to be uploaded to your backend");
tx.complete().await?;
}
Ok(())
}
}
```
### 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 Tauri SDK exposes the same JavaScript database 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
The Rust SDK uses the `log` crate which can be enabled using the [Tauri logging plugin](https://v2.tauri.app/plugin/logging/).
## Sharing a Database with Rust Code
A `PowerSyncTauriDatabase` instance can be shared with Rust code:
1. Call and await `.init()` on the database to ensure the database has been opened.
2. Use the `.rustHandle` getter, which returns a number representing the database instance.
3. This handle can now be passed as an argument to one of your Tauri commands.
In Rust SDK, you can use `AppHandle::powersync()` and
`PowerSync::database_from_javascript_handle` to inspect the database from Rust.
See the [Rust SDK guide](/client-sdks/reference/rust) for more information.
Connection locks and table updates are automatically shared between Rust and JavaScript code.
## Limitations
* The Rust SDK, which is used to implement the Tauri plugin, does not provide `lastSyncedAt`, `hasSynced` and `priorityStatusEntries` on `SyncStatus`.
Use the status on individual Sync Streams through `SyncStatus.forStream` instead.
* Connecting to the PowerSync Service is only possible from Rust. Calling `connect()` from JavaScript
will throw.
## 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.