---
title: BLOB storage and providers
slug: cms-11/dev-docs/rghf-blob-storage-and-providers
docTags: 
createdAt: 2026-07-22T19:45:22.322Z
---

BLOB providers are a framework designed to store large amounts of binary data in an optimized and cost-effective solution, such as cloud storage instead of a database.

## BLOB providers

The Optimizely platform supports BLOB storage of assets using a provider-based setup and has a built-in file BLOB provider. You have the following options:

- **Built-in BLOB provider** for media files such as images, videos, and documents stored on a local disc or a file share defined during installation.
- **Customized BLOB provider** for your specific hosting environment, such as BLOB providers for Microsoft Azure and Amazon Web Services, available from the [Optimizely NuGet feed](http://nuget.optimizely.com).

## BLOB architecture

A provider is responsible for storing a data stream and associating it with a unique identifier. You group BLOBs into containers, a logical name for a set of BLOBs you can delete with a single API call. It exposes the unique identifier as a URI in the format `epi.fx.blob://[provider]/[container]/[blob]` to store a reference to a BLOB in a database.

Most methods in the API return a reference even though the actual BLOB does not exist because it would be too costly to access a cloud service every time; for example, a call to `GetBlob` is made, and the caller is assumed to keep track of BLOB identifiers.

The example below shows how to use a BLOB provider.

```csharp
public void ReadWriteBlobs() {
  var blobFactory = ServiceLocator.Current.GetInstance<IBlobFactory>();

  //Define a container
  var container = Blob.GetContainerIdentifier(Guid.NewGuid());

  //Uploading a file to a blob
  var blob1 = blobFactory.CreateBlob(container, ".png");
  using(var fs = new FileStream("c:\\myfile.png", FileMode.Open)) {
    blob1.Write(fs);
  }

  //Writing custom data to a blob
  var blob2 = blobFactory.CreateBlob(container, ".txt");
  using(var s = blob2.OpenWrite()) {
    var w = new StreamWriter(s);
    w.WriteLine("Hello World!");
    w.Flush();
  }

  //Reading from a blob based on ID
  var blobID = blob2.ID;
  var blob3 = blobFactory.GetBlob(blobID);
  using(var s = blob3.OpenRead()) {
    var helloWorld = new StreamReader(s).ReadToEnd();
  }

  //Delete single blob
  blobFactory.Delete(blobID);

  //Delete container
  blobFactory.Delete(container);
}
```

:::hint{type="info"}
**Note**
When you delete a container under the website root, if you use the `FileBlob` provider, it leaves empty folders under the website root. If you use the Azure or the Amazon provider, it deletes the containers. For information about handling media in the assets pane, see [Work with media](docId\:zQ_0gdiWK9lzJVG9dkrZJ).
:::

## Configuring a custom BLOB provider

Add a BLOB element to the episerver.framework section in `web.config` to define a custom provider:

```xml
<episerver.framework>
      <blob defaultProvider="myProvider">
        <providers>
          <add name="myProvider" type="MyAssembly.Provider, MyAssembly" />
        </providers>
      </blob>
    </episerver.framework>
```

Another option is to add the BLOB provider programmatically during the configuration phase of the site initialization. Create an initialization module that implements the `IConfigurableModule` interface and handle the registration in the `ConfigureContainer` method through one of the extension methods available on the `context.Services` property or by configuring the `BlobOptions` class directly.

```csharp
[InitializableModule]
[ModuleDependency(typeof (FrameworkInitialization))]
public class CustomBlobProviderInitialization: IConfigurableModule {
  public void ConfigureContainer(ServiceConfigurationContext context) {
    // This provider will be added as the default
    context.Services.AddFileBlobProvider("myFileBlobProvider", @ "c:\path\to\file\blobs");
    context.Services.AddBlobProvider<MyCustomBlobProvider>("myCustomBlobProvider",
      default: false);
    context.Services.Configure<BlobOptions>(o => {
      o.AddProvider<MyCustomBlobProvider>("anotherCustomBlobProvider");
      o.DefaultProvider = "anotherCustomBlobProvider";
    });
  }

  public void Initialize(InitializationEngine context) {}
  public void Uninitialize(InitializationEngine context) {}
}
```