Author: Chris Bahr, Created: 2026-01-13

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Early Access: This content outlines functionality available only to select partners and internal users

Developer Studio Setup

Developer Studio streamlines the custom development process by acting as a stand-alone application that connects with OneStream environments and creates local copies of business rules and workspace assembly files.

With Developer Studio, you can:

• Setup and manage repositories for project files.
• Push and pull changes to files between the OneStream server and your local environment.
• Modify code locally in any IDE.
• Download reference assemblies and integrate IntelliSense capabilities.

Prerequisites

• Minimum OneStream Platform version: 9.2.0

0. Developer Studio Installation

Download and Install Developer Studio

1. Create a Repository

Step 1.1:

Create a parent folder where you will store your code locally (e.g., C:\DeveloperStudio). This will serve as a parent repository to host all of your repositories and display a high-level view of your repository items

Step 1.2:

Launch Developer Studio. Click Add Repository or File > Add Repository. Give it a name. Set the Repository Root Folder to the folder which you created in Step 1.

Click Save

2. Add an Item

We will next link a local project within our Repository to a Workspace Assembly in OneStream. There are two ways to do this when selecting the Project Source. You can either create a new project locally from a Workspace Assembly in OneStream, or select an existing project from local and link it to a Workspace Assembly in OneStream.

Step 2.1 Option A - New Project From OneStream

If you are starting from a clean slate locally and looking to pull in an Assembly from OneStream:

1. create a new folder within your Repository for the Assembly you will be pulling.

   1. (E.g., if I am creating a new project locally from OneStream source called MyFirstDataPipeline, I will have this folder path (C:\DeveloperStudio\MyFirstDataPipeline).

2. Click Add Item

   1. Enter a name for the Item
   2. Project Source: New Project from OneStream
   3. Select the newly created directory within your Repository
   4. Find and select the Assembly you’d like to pull into your local Repository
   5. Click Save

3. A Pull Results dialog will appear showing the results

Step 2.1 Option B - Existing Project from Local

If there is a project you have locally and you’d like to link it to a OneStream Assembly:

1. Ensure the Assembly to link exists in OneStream

At the time of writing, there is no ability to create a new Workspace Assembly in OneStream using a local project. Thus, in order to initialize a connection between a local project and a OneStream Assembly, the Assembly must first exist in OneStream.

When creating an Item in Developer Studio, it is not required that the names of your local project and the OneStream Assembly match, so take caution when setting up Items as to not overwrite the wrong workspace assembly.

2. Ensure the project exists within your Repository

3. Click Add Item

   1. Enter a name for the Item
   2. Project Source: Existing Project from Local
   3. Select the Project File you would like to link to the OneStream Assembly
   4. Find and select the Assembly you’d like to connect
   5. Click Save

4. A dialog will appear offering the option to pull the latest code files into your local project.

   1. Select Do Not Pull if you would not like to overwrite your local project with the OneStream Assembly
   2. Select Pull Latest if you would like to overwrite your local project with the OneStream Assembly

3. Sync Changes

Step 3.1

With your item created, you can now push or pull changes to and from OneStream.

Select your Repository Item(s) within Developer Studio, and use Pull Selected to overwrite your local project with the OneStream Assembly, or Push Selected to overwrite the OneStream Assembly with your local.

4. Download the OneStream Reference Assemblies

Step 4.1

Within Developer Studio, click File > Download OneStream Reference Assemblies. Place the downloaded NuGet package in a location you’ll remember, such as C:\LocalNuGetFeed.

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Cursor Extensions

This section outlines some recommended extensions to use with .NET development for Cursor and is subject to change.

1. Install Extensions

1. C# by Anysphere

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XBR / OneStream Reference Assembly Installation

1. Download the XBR NuGet Package

Download the Xperiflow.<version>.nupkg and save it to a folder on your machine, such as C:\LocalNuGetFeed

2. Add the Packages

Option A: Cursor / VS Code

1. Open the terminal (View → Terminal, or Terminal → New Terminal)
2. Navigate to the directory containing the .csproj file you want to reference XBR/OneStream Reference Assemblies from
3. In the command below, provide the path to where the downloaded NuGet packages are stored:

dotnet add package <package_name> --version <version> --source <path-to-dir-with-downloaded-nupkg>

dotnet add package Xperiflow --version 4.1.0 --source C:\LocalNuGetFeed
dotnet add package OneStream.ReferenceAssemblies --version 9.2.0 --source C:\LocalNuGetFeed

3. Restart the C# extension if IntelliSense doesn’t appear immediately

   1. Ctrl+Shift+P → “Restart Lanuage Server”
   2. Or reload the window: Ctrl+Shift+P → “Developer: Reload Window”

Option B: Visual Studio

1. Right click your project in Solution Explorer → Manage NuGet Packages

2. Click the gear icon () next to the Package Source dropdown (top right)

3. click the + button to add a new source:

   1. Name: Local
   2. Source: Enter the path to the downloaded NuGet Package

4. Click Update, then OK

5. Back in NuGet Package Manager

   1. Select Local from the Package Source dropdown
   2. Search for Xperiflow
   3. Click Install

Option C: Command Line (dotnet CLI)

1. Navigate to the directory containing the .csproj file you want to reference XBR/OneStream Reference Assemblies from
2. In the command below, provide the path to where the downloaded NuGet packages are stored

dotnet add package Xperiflow --version 4.1.0 --source C:\LocalNuGetFeed
dotnet add package OneStream --version 9.2.0 --source C:\LocalNuGetFeed

3. Use XBR / OneStream in your IDE

Step 4: Use XBR in Code

All XBR types are under the Workspace.XBR.Xperiflow.<...> namespace

using OneStream.Shared.Wcf;
using Workspace.XBR.Xperiflow;
using Workspace.XBR.Xperiflow.MetaFileSystem;

public class Class1
{
    public void Test(SessionInfo si)
    {
        IMetaFileSystemClient metaFileSystemClient = XBRApi.MetaFileSystem.GetMetaFileSystemClient(si, MetaFileSystemLocation.Shared);
        metaFileSystemClient.WriteFileAsync("hello.txt", "Hello, World!").Wait();
        BRApi.ErrorLog.LogMessage(si, "File written!");
    }
}