Source Code

Refer to the powersync-dotnet repo on GitHub.

API Reference (Coming soon)

A full API Reference for this SDK is not yet available. This is planned for a future release.

Example App

A small CLI app showcasing bidirectional sync.

This SDK is currently in an alpha release. It is not suitable for production use as breaking changes may still occur.

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Supported Frameworks and Targets

The PowerSync .NET SDK supports:

  • .NET Versions: 6, 8, and 9
  • .NET Framework: Version 4.8 (requires additional configuration)

Current Limitations:

  • The SDK in its current state is designed for desktop, server, and traditional binary applications.
  • Web and mobile platforms (Blazor, MAUI) are not yet supported, but are planned.

For more details, please refer to the package Readme.

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SDK Features

  • Provides real-time streaming of database changes.
  • Offers direct access to the SQLite database, enabling the use of SQL on both client and server sides.
  • Enables subscription to queries for receiving live updates.
  • Eliminates the need for client-side database migrations as these are managed automatically.

​
Quickstart

Add the PowerSync .NET NuGet package to your project:

dotnet add package PowerSync.Common --prerelease

Add --prerelease while this package is in alpha.

Next, make sure that you have:

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1. Define the schema

The first step is defining the schema for the local SQLite database.

This schema represents a “view” of the downloaded data. No migrations are required — the schema is applied directly when the local PowerSync database is constructed (as we’ll show in the next step). You can use this example as a reference when defining your schema.

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2. Instantiate the PowerSync Database

Next, you need to instantiate the PowerSync database — this is the core managed database.

Its primary functions are to record all changes in the local database, whether online or offline. In addition, it automatically uploads changes to your app backend when connected.

Example:

using PowerSync.Common.Client;

class Demo
{
    static async Task Main()
    {
        var db = new PowerSyncDatabase(new PowerSyncDatabaseOptions
        {
            Database = new SQLOpenOptions { DbFilename = "tododemo.db" },
            Schema = AppSchema.PowerSyncSchema,
        });
        await db.Init();
    }
}

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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. Apply local changes on your backend application server (and from there, to Postgres)

Accordingly, the connector must implement two methods:

  1. PowerSyncBackendConnector.FetchCredentials - This is called every couple of minutes and is used to obtain credentials for your app backend API. -> See Authentication Setup for instructions on how the credentials should be generated.
  2. PowerSyncBackendConnector.UploadData - Use this to upload client-side changes to your app backend. -> See Writing Client Changes for considerations on the app backend implementation.

Example:

using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using PowerSync.Common.Client;
using PowerSync.Common.Client.Connection;
using PowerSync.Common.DB.Crud;

public class MyConnector : IPowerSyncBackendConnector
{
    private readonly HttpClient _httpClient;
    
    // User credentials for the current session
    public string UserId { get; private set; }
    
    // Service endpoints
    private readonly string _backendUrl;
    private readonly string _powerSyncUrl;
    private string? _clientId;

    public MyConnector()
    {
        _httpClient = new HttpClient();
        
        // In a real app, this would come from your authentication system
        UserId = "user-123"; 
        
        // Configure your service endpoints
        _backendUrl = "https://your-backend-api.example.com";
        _powerSyncUrl = "https://your-powersync-instance.powersync.journeyapps.com";
    }

    public async Task<PowerSyncCredentials?> FetchCredentials()
    {
        try {
            // Obtain a JWT from your authentication service.
            // See https://docs.powersync.com/installation/authentication-setup
            // If you're using Supabase or Firebase, you can re-use the JWT from those clients, see
            // - https://docs.powersync.com/installation/authentication-setup/supabase-auth
            // - https://docs.powersync.com/installation/authentication-setup/firebase-auth

            var authToken = "your-auth-token"; // Use a development token (see Authentication Setup https://docs.powersync.com/installation/authentication-setup/development-tokens) to get up and running quickly

            // Return credentials with PowerSync endpoint and JWT token
            return new PowerSyncCredentials(_powerSyncUrl, authToken);
            
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error fetching credentials: {ex.Message}");
            throw;
        }
    }

    public async Task UploadData(IPowerSyncDatabase database)
    {
        // Get the next transaction to upload
        CrudTransaction? transaction;
        try
        {
            transaction = await database.GetNextCrudTransaction();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"UploadData Error: {ex.Message}");
            return;
        }

        // If there's no transaction, there's nothing to upload
        if (transaction == null)
        {
            return;
        }

        // Get client ID if not already retrieved
        _clientId ??= await database.GetClientId();

        try
        {
            // Convert PowerSync operations to your backend format
            var batch = new List<object>();
            foreach (var operation in transaction.Crud)
            {
                batch.Add(new
                {
                    op = operation.Op.ToString(),  // INSERT, UPDATE, DELETE
                    table = operation.Table,
                    id = operation.Id,
                    data = operation.OpData
                });
            }

            // Send the operations to your backend
            var payload = JsonSerializer.Serialize(new { batch });
            var content = new StringContent(payload, Encoding.UTF8, "application/json");

            HttpResponseMessage response = await _httpClient.PostAsync($"{_backendUrl}/api/data", content);
            response.EnsureSuccessStatusCode();

            // Mark the transaction as completed
            await transaction.Complete();
        }
        catch (Exception ex)
        {
            Console.WriteLine($"UploadData Error: {ex.Message}");
            throw;
        }
    }
}

With your database instantiated and your connector ready, call connect to start the synchronization process:

await db.Connect(new MyConnector());
await db.WaitForFirstSync(); // Optional, to wait for a complete snapshot of data to be available

​
Usage

After connecting the client database, it is ready to be used. You can run queries and make updates as follows:

// Use db.Get() to fetch a single row:
Console.WriteLine(await db.Get<object>("SELECT powersync_rs_version();"));

// Or db.GetAll() to fetch all:
// Where List result is defined:
// record ListResult(string id, string name, string owner_id, string created_at);
Console.WriteLine(await db.GetAll<ListResult>("SELECT * FROM lists;"));

// Use db.Watch() to watch queries for changes (await is used to wait for initialization):
await db.Watch("select * from lists", null, new WatchHandler<ListResult>
{
  OnResult = (results) =>
  {
      Console.WriteLine("Results: ");
      foreach (var result in results)
      {
          Console.WriteLine(result.id + ":" + result.name);
      }
  },
  OnError = (error) =>
  {
      Console.WriteLine("Error: " + error.Message);
  }
});

// And db.Execute for inserts, updates and deletes:
await db.Execute(
  "insert into lists (id, name, owner_id, created_at) values (uuid(), 'New User', ?, datetime())",
  [connector.UserId]
);

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Logging

Enable logging to help you debug your app. By default, the SDK uses a no-op logger that doesn’t output any logs. To enable logging, you can configure a custom logger using .NET’s ILogger interface:

using Microsoft.Extensions.Logging;
using PowerSync.Common.Client;

// Create a logger factory
ILoggerFactory loggerFactory = LoggerFactory.Create(builder =>
{
    builder.AddConsole();             // Enable console logging
    builder.SetMinimumLevel(LogLevel.Information);  // Set minimum log level
});

var logger = loggerFactory.CreateLogger("PowerSyncLogger");

var db = new PowerSyncDatabase(new PowerSyncDatabaseOptions
{
    Database = new SQLOpenOptions { DbFilename = "powersync.db" },
    Schema = AppSchema.PowerSyncSchema,
    Logger = logger
});

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