README.md

July 23, 2026 · View on GitHub

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One Interface To Rule Them All

FluentStorage is a fully managed polycloud .NET cloud storage library, optimized for speed. It helps you interface with multiple cloud providers from a single unified API, allowing you to switch cloud providers or support multiple cloud providers without any logic changes.

FluentStorage is released under the permissive MIT License, so it can be used in both proprietary and free/open source applications. FluentStorage is written entirely in C# with no configuration files required.

Features

Common features
- Unified polycloud API for Object storage and Queue messaging across all cloud storage providers
- Each provider has its own Nuget package with zero configuration required.
- Fully asynchronous API with identical behavior across all providers
- Unified path system that works across all providers
- Object manipulation commands like create/get/set/move/delete
- High-level API to easily upload/download files
- High-level API to easily upload/download directories or virtual directories with rule-based filtering, progress callbacks, ability to only re-transfer changed files, and a detailed transfer report provided at the end
- Easily work with any object using read streams, write streams and seekable streams
- File streaming support to provide video playback on top of object stores
- Fast server-side checksum computation for Azure, GCP, FTP, SFTP, with a fallback to client-side hashing for other providers
- Object metadata, including reading and writing object info, length, timestamps, etc
- Memory and local disk providers, so you can test on a local machine or access attached NAS/EBS drives
- Large suite of integration tests and some performance tests that work across all providers, which are easily configured to run against your own clouds
Specially for object storage
- Presigned URL generation, with AWS-friendly and Azure-friendly API signatures
- Virtual directory manipulation
- Object versions, including fetching older versions, deleting a version, etc
- Object tagging, including adding and removing tags
- Object storage tier or storage class modification
Specially for SFTP and FTP
- Directory listing & Directory manipulation
- Fast server-side file checksums using native FTP and SSH commands
- SSH command engine for SFTP provider, to execute native SSH commands with automatic OS and utility detection
- File permissions/CHMOD modification
- Get detailed server metadata and OS information

Storage Providers

FluentStorage supports the following cloud storage providers:

Documentation Link	Factory class	Store class	`GetClient()` returns
AWS S3	`AwsS3Storage`	`S3Store`	`AmazonS3Client`
Azure Blobs	`AzureBlobStore`	`AzureBlobStore`	`BlobServiceClient`
Azure Files	`AzureFilesStorage`	`AzureFilesStore`	`ShareServiceClient`
Azure DataLake	`AzureDataLakeStorage`	`AzureDataLakeStore`	`ExtendedSdk`
GCP	`GoogleCloudStorage`	`GoogleCloudStore`	`StorageClient`
MinIO (native)	`MinioStorage`	`MinioStore`	`MinioClient`
MinIO (S3)	`MinioS3Storage`	`S3Store`	`AmazonS3Client`
Cloudflare R2	`CloudflareR2Storage`	`S3Store`	`AmazonS3Client`
DigitalOcean Spaces	`DigitalOceanSpacesStorage`	`S3Store`	`AmazonS3Client`
Wasabi	`WasabiStorage`	`S3Store`	`AmazonS3Client`
Backblaze B2	`BackblazeB2Storage`	`S3Store`	`AmazonS3Client`
Hetzner	`HetznerStorage`	`S3Store`	`AmazonS3Client`
Vultr	`VultrStorage`	`S3Store`	`AmazonS3Client`
MongoDB GridFS	`MongoGridStorage`	`MongoGridStore`	`MongoClient`
Alibaba OSS	`AlibabaStorage`	`AlibabaStore`	`OssClient`
FTP	`FtpStorage`	`FtpStore`	`AsyncFtpClient`
SFTP	`SftpStorage`	`SftpStore`	`SftpClient`
Local Disk	`StorageFactory`	`DiskStore`	`IFileSystem`

To add support for a new S3-compatible provider, search for [ADD STORAGE PROVIDER] across all code files.

Polycloud API

This table shows the API supported by IStore across various cloud and server providers.

API	Azure Blobs	Azure Files	AWS S3	GCP	MinIO	Mongo	Alibaba	FTP	SFTP	Disk
System information
GetClient	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetServer	❌	❌	❌	❌	❌	✔️	❌	✔️	✔️	✔️
File listing
ListDirectory	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
ListObjects	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
File upload / download
GetObject	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
SetObject	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetBytes	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
SetBytes	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
DownloadObject	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
UploadObject	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
OpenRead	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
OpenWrite	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
API	Azure Blobs	Azure Files	AWS S3	GCP	MinIO	Mongo	Alibaba	FTP	SFTP	Disk
Directory upload / download
DownloadDirectory	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
UploadDirectory	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
Directory manipulation
IsFileSystem	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
DirectoryExists	✔️	❌	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
CreateDirectory	✔️	❌	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
DeleteDirectory	✔️	❌	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
MoveDirectory	❌	❌	❌	❌	❌	❌	❌	✔️	✔️	✔️
API	Azure Blobs	Azure Files	AWS S3	GCP	MinIO	Mongo	Alibaba	FTP	SFTP	Disk
File streaming / seeking
IsSeekable	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
OpenRange	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
OpenSeekable	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
File manipulation
ObjectExists	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
MoveObject	✔️	❌	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
DeleteObject	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
DeleteObjects	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
File metadata
GetObjectChecksum	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetObjectLength	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetObjectInfo	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetObjectsInfo	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
SetObjectInfo	✔️	✔️	✔️	✔️	✔️	✔️	✔️	❌	❌	✔️
SetObjectsInfo	✔️	✔️	✔️	✔️	✔️	✔️	✔️	❌	❌	✔️
API	Azure Blobs	Azure Files	AWS S3	GCP	MinIO	Mongo	Alibaba	FTP	SFTP	Disk
File versioning
IsVersioned	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
ListObjectVersions	✔️	🚫	✔️	✔️	🚫	🚫	🚫	🚫	🚫	🚫
GetObjectVersion	✔️	🚫	✔️	✔️	🚫	🚫	🚫	🚫	🚫	🚫
RestoreObjectVersion	✔️	🚫	✔️	✔️	🚫	🚫	🚫	🚫	🚫	🚫
DeleteObjectVersion	✔️	🚫	✔️	✔️	🚫	🚫	🚫	🚫	🚫	🚫
File tagging
IsTagged	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetObjectTags	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
SetObjectTags	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
DeleteObjectTags	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
File storage tier
IsTiered	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️	✔️
GetObjectTier	✔️	🚫	✔️	✔️	✔️	🚫	🚫	🚫	🚫	🚫
SetObjectTier	✔️	🚫	✔️	✔️	✔️	🚫	🚫	🚫	🚫	🚫
API	Azure Blobs	Azure Files	AWS S3	GCP	MinIO	Mongo	Alibaba	FTP	SFTP	Disk
Presigned URL generation
GetUploadUrl	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
GetDownloadUrl	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
GetPresignedUrl	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
GetObjectSas	✔️	🚫	✔️	✔️	✔️	🚫	✔️	🚫	🚫	🚫
File permissions
GetFilePermissions	❌	❌	❌	❌	❌	❌	❌	✔️	✔️	❌
SetFilePermissions	❌	❌	❌	❌	❌	❌	❌	✔️	✔️	❌

Provider API

This table shows the API supported by specific cloud providers:

Azure Blobs	Azure Data Lake	AWS S3
`IAzureBlobStore`	`IAzureDataLakeStore`	`IS3Storage`
AcquireLease BreakLease GetContainerPublicAccess SetContainerPublicAccess GetStorageSas GetContainerSas	ListFilesystems CreateFilesystem DeleteFilesystem GetAccessControl SetAccessControl	SetAcl

Queue Providers

FluentStorage supports the following queue/messaging providers:

	Documentation Link	Factory class
	AWS SQS	`AwsSqsStorage`
	Azure Queue	`AzureQueueStorage`
	Azure Service Bus	`AzureServiceBus`

Packages

Stable binaries are released on NuGet, and contain everything you need to use Cloud Storage in your .NET app.

	Package	Latest Version	Downloads	Documentation
	FluentStorage			Standard
	FluentStorage.AWS			S3, SQS
	FluentStorage.GCP			GCP
	FluentStorage.Azure			---
	FluentStorage.Azure.Blobs			Blob
	FluentStorage.Azure.Files			File
	FluentStorage.Azure.ServiceBus			ServiceBus
	FluentStorage.Azure.KeyVault			KeyVault
	FluentStorage.Azure.Queues			Queue
	FluentStorage.Minio			Minio
	FluentStorage.Mongo			Mongo
	FluentStorage.Alibaba			Alibaba
	FluentStorage.FTP			FTP
	FluentStorage.SFTP			SFTP

Concept Mapping

This table shows the API and the provider-specific concept it maps to:

Concept	AWS S3	Azure Blob	GCP
Versioning API	Object Versions	Blob Versions	Object Generations
Tagging API	Object Tags	Blob Index Tags / Blob Tags	Custom Metadata
Metadata API	Object Metadata	Blob Metadata	Object Metadata
Storage Tier	Storage Class	Access Tier	Storage Class
Retention API (planned)	Object Lock Retention	Immutability Policy	Retention Policy
Locking API (planned)	Object Lock Configuration / Legal Hold	Legal Hold + Immutability Policy	Object Holds

Storage Tier Mapping

This table shows the FluentStorage StorageTier enum and the provider-specific tier it maps to:

Concept	AWS S3	Azure Blob	GCP
`StorageTier.Standard`	`STANDARD`	`Hot`	`STANDARD`
`StorageTier.Intelligent`	`INTELLIGENT_TIERING`	`AutoTiering`	`AUTOCLASS`
`StorageTier.Nearline`	`STANDARD_IA`	`Cool`	`NEARLINE`
`StorageTier.Cold`	`GLACIER_IR`	`Cold`	`COLDLINE`
`StorageTier.Archive`	`GLACIER`	`Archive`	`ARCHIVE`
`StorageTier.DeepArchive`	`DEEP_ARCHIVE`	`Archive`	`ARCHIVE`

Platform Support

FluentStorage works on .NET and .NET Standard/.NET Core.

Platform	Binaries Folder
.NET 7.0	net70
.NET 8.0	net80
.NET 9.0	net90
.NET Standard 2.0	netstandard2.0
.NET Standard 2.1	netstandard2.1

FluentStorage is also supported on these platforms: (via .NET Standard)

Mono 4.6
Xamarin.iOS 10.0
Xamarin.Android 10.0
Universal Windows Platform 10.0

Binaries for all platforms are built from a single Visual Studio Project. You will need the latest Visual Studio to build or contribute to FluentStorage.

Architecture

Without FluentStorage

Today, most cloud applications and services are developed against vendor-specific APIs like Amazon S3 API or Azure Blob API for cloud storage capabilities.

Using multiple vendor-specific APIs can increase your vendor lock-in, and makes your application more complex and harder to maintain. And sometimes these APIs may not offer all the functionality you need for your application. Polycloud also becomes very hard to implement.

Arch

With FluentStorage

What if we had a single, consistent API to deal with all types of cloud storage? That would solve these issues and bring more flexibility in switching cloud providers or cloud services.

Thus was born the idea for FluentStorage.

You can use a single, consistent API to interact with multiple cloud providers, where each provider is supported through its own special Nuget package.

Arch

Documentation

Check the Wiki.

What's New

In 2026, we added:

Version 8 with a massive redesign of the entire API and behaviour
MongoDB GridFS provider using native MongoDB Driver
MinIO provider using native Minio SDK
Alibaba OSS provider using native Aliyun SDK
Cloudflare R2 provider using S3-compatible SDK
Backblaze B2 provider using S3-compatible SDK
Hetzner provider using S3-compatible SDK
Vultr provider using S3-compatible SDK
Azure.Identity support for Azure Files with token credential, client secret, and managed identity authentication.
Wiki pages per provider
Removed unused packages: Databricks, EventHub, DataLake Gen 1, ServiceFabric

In 2025, we added:

Azure.Identity support for Azure Blobs with token credential, client secret, and managed identity authentication.

In 2024, we added:

DigitalOcean Spaces provider
MinIO provider
Wasabi provider

In 2023, we added:

SFTP provider SSH.NET added
FTP provider FluentFTP updated to v44
AWS Nuget bumped to latest versions
Wiki created for documentation
Platform support updated to netstandard2.0,netstandard2.1,net50,net60

Similar Libraries

Foundatio - Caching, Messaging, Queues and Storage library with AWS, Azure and many other providers
SlimMessageBus - Messaging library with providers like RabbitMQ, Kafka, Azure EventHub, MQTT, Redis
ManagedCode.Storage - Storage library with AWS, Azure, GCP and other providers

Sponsorship

FluentStorage has received major sponsorship from these generous organizations:

Microsoft Corporation

Has FluentStorage made a difference for you or your organization? If so, consider becoming a sponsor to help keep the project thriving. Even a small monthly contribution, like $20, can make a meaningful impact.

Contributors

Special thanks to these awesome people who helped create FluentStorage!