How to Connect to QuickBooks Online in .NET With C#

Why dotConnect for QuickBooks?

Easy integration with QuickBooks Online

Ensures effortless connection to QuickBooks Online, allowing .NET applications to access accounting data such as customers, invoices, and payments without dealing with the complexity of the API.

Interactive OAuth token generation

Streamlines authentication via Interactive OAuth, where users sign in through a browser-based login flow. After authorization, dotConnect automatically gets and manages access and refresh tokens.

User-friendly ADO.NET classes

Uses well-known ADO.NET classes, enabling an easy start and creating a convenient working environment.

Advanced ORM support

Fully supports EF Core, Dapper, NHibernate, LinqConnect, and other technologies for efficient QuickBooks Online data management.

Full ADO.NET compliance

Conforms to the latest ADO.NET standards and innovations for seamless integration with .NET applications.

Priority support & frequent updates

Includes priority support, detailed documentation, and regular updates for continuous improvement.

Download and activate dotConnect for QuickBooks

You can start using dotConnect for QuickBooks immediately with a 30-day free trial. Choose one of the following installation options:

30-day free trial version

dotnet add package Devart.Data.QuickBooks

Install-Package Devart.Data.QuickBooks

Start using dotConnect for QuickBooks in your project today with a free trial

Free 30-day trial

Establish the connection

dotConnect for QuickBooks Online uses an interactive OAuth authorization flow to obtain access tokens and establish a connection with the data source. This approach enables secure data access without requiring the application to handle user credentials.

When a connection is opened for the first time, the provider launches a browser window, prompting the user to complete the authorization process. Once authorization is granted, the access tokens are securely stored, and subsequent connections can be established without additional user interaction. You only need to provide a valid license key.

This interactive authentication flow improves security while giving users full control over access permissions.

Here is the sample code that will help you connect to QuickBooks Online. Complete it with the following credentials: Client Id, Company Id, Client Secret, Refresh token, and License key. Additionally, set Sandbox to true if you are using the sandbox application type.

using System.Data;
using Devart.Data.QuickBooks;

class Program
{
  static void Main()
  {
    using QuickBooksConnection conn = new(
      "Authentication Type=OAuthInteractive;" +
      "License Key=**********");
    conn.Open();

    using QuickBooksCommand cmd = new(
      "SELECT Id, Name, FullyQualifiedName, Description FROM Account", conn);

    using QuickBooksDataReader reader = cmd.ExecuteReader();

    if (!reader.HasRows)
    {
      Console.WriteLine("No data found in the Account table.");
      return;
    }

    while (reader.Read())
    {
      string id          = reader["Id"]?.ToString()                 ?? "N/A";
      string name        = reader["Name"]?.ToString()               ?? "N/A";
      string fqn         = reader["FullyQualifiedName"]?.ToString() ?? "N/A";
      string description = reader["Description"]?.ToString()        ?? "N/A";

      Console.WriteLine($"Id:                 {id}");
      Console.WriteLine($"Name:               {name}");
      Console.WriteLine($"FullyQualifiedName: {fqn}");
      Console.WriteLine($"Description:        {description}");
      Console.WriteLine(new string('-', 50));
    }
  }
}

Once you successfully connect your application to QuickBooks Online, you will be able to fetch and manage your data.

Connection string examples

In .NET applications, a connection string is a formatted string that provides the information required to establish a connection to a data source.

At its core, the connection string tells the provider where to connect, how to authenticate, and what settings to use during the connection process. Once supplied, the data provider parses the string, validates its syntax, and ensures that all specified keywords are supported. After this initial validation, the extracted parameters are passed to the data source, which performs additional checks and ultimately establishes the connection.

The table below outlines some of the most commonly used connection string parameters.

For a complete list of parameters and detailed descriptions, refer to the official guidelines.

Conclusion

You can now connect your C# application to QuickBooks Online using dotConnect for QuickBooks. With the connection in place, you can extend your application to perform a wide range of operations, such as querying customers, invoices, and accounts, as well as creating, updating, and managing QuickBooks data programmatically.

And if you want firsthand experience, feel free to download dotConnect for QuickBooks Online for a free 30-day trial. Give it a go under the real workload!

FAQ