---
title: "@microsoft/rayfin-storage"
description: "Type-safe blob storage client for Rayfin — what it's for and how to model storage folders today, pending a version-locked API reference."
url: https://rayfin.ai/docs/reference/sdk/rayfin-storage
markdown_url: https://rayfin.ai/docs/reference/sdk/rayfin-storage.md
section: reference
product: Rayfin
sdk_version: 1.34.0
cli_version: 1.33.2
last_updated: 2026-08-23T15:47:11-07:00
source: reference/sdk/rayfin-storage.mdx
---

# @microsoft/rayfin-storage

> Type-safe blob storage client for Rayfin — what it's for and how to model storage folders today, pending a version-locked API reference.

`@microsoft/rayfin-storage` is Rayfin's type-safe blob storage client. Per the package
catalog, it provides a storage client for Rayfin storage backends (blob upload, download,
and file management).

> [!WARNING]
> Storage is experimental and is not available in every Fabric region or tenant.
> `@microsoft/rayfin-storage` may change substantially between releases.

> [!NOTE]
> `@microsoft/rayfin-storage` is not installed in the environment this reference was
> written against, so its method signatures cannot be verified here. Run
> `rayfin docs search 'storage' --module ts-sdk` (or the MCP server's
> `search_docs(query: 'storage', module: 'ts-sdk')`) from your project root for the
> version-locked API surface of the package you actually have installed. See
> [MCP server](/docs/reference/cli/docs#mcp-server) for how those lookups work.

## Installation [#installation]

```bash
npm install @microsoft/rayfin-storage
```

Storage is also gated behind a CLI feature flag in current builds — set
`RAYFIN_FEATURE_FLAGS=storage` to expose storage prompts in `rayfin init`.

## What is verifiable today [#what-is-verifiable-today]

The one part of the storage model that is verified independently — because it lives in
`@microsoft/rayfin-core`, which *is* installed — is the `@blob()` class decorator you use
to declare a storage folder:

```typescript
import { blob, role } from '@microsoft/rayfin-core';

@blob('uploads')
@role('authenticated', '*')
export class FileModel {
  owner_id!: string;
}
```

* `@blob(folderName?)` marks a class as a blob storage folder. The name defaults to the
  kebab-case class name when omitted.
* Permissions use the same `@role()` / `@authenticated()` / `@anonymous()` decorators as
  data entities (see [`@microsoft/rayfin-core`](/docs/reference/sdk/rayfin-core)) — a
  folder is inferred public if the `anonymous` role has any granted permission on it,
  otherwise private.

`@blob()` is what the Rayfin CLI reads to generate storage configuration when you run
`rayfin up`. It does not, by itself, give you a client to upload or download files — that
surface belongs to `@microsoft/rayfin-storage` and is out of scope for this page.

## What this page deliberately omits [#what-this-page-deliberately-omits]

No client construction signature, upload/download method names, or options are documented
here, because none could be confirmed against either the vendored package docs or an
installed copy of the package. Documenting a guessed method signature would be worse than
leaving it out — use the `rayfin docs` lookup above to get the real surface for your
project's installed version.