Foundatio is an open-source C# library, published on NuGet under the Apache-2.0 licence, that provides pluggable foundation blocks — caching, queues, distributed locks, messaging, background jobs, file storage, and resilience — for building loosely coupled distributed applications.

What it is

Foundatio is an interface-first library for .NET. Applications code against abstractions such as ICacheClient, IQueue, IFileStorage, and ILockProvider instead of against a specific vendor SDK, and the same patterns repeat across caching, queues, storage, messaging, and locks. It ships in-memory implementations including InMemoryCacheClient, InMemoryQueue, and InMemoryFileStorage, plus a CacheLockProvider for distributed locking, and it is built for Microsoft.Extensions.DependencyInjection. Provider implementations live in separate packages, among them Foundatio.Redis, Foundatio.AzureStorage, Foundatio.AzureServiceBus, Foundatio.AWS, Foundatio.RabbitMQ, Foundatio.Kafka, Foundatio.Minio, Foundatio.Aliyun, and Foundatio.Storage.SshNet.

The concrete problem it solves is provider lock-in and duplicated plumbing. A team that needs a cache, a queue, pub/sub, file storage, and a distributed lock would normally write separate integration code for Redis, Azure, AWS, RabbitMQ, or Kafka, then rewrite it when the backing service changes. Foundatio replaces that work with one set of abstractions and consistent APIs, so a Redis, Azure, AWS, or in-memory backend can be swapped with no code changes. Retry policies, circuit breakers, and timeouts are folded into the same model through the resilience block.

Key capabilities

• Caching with in-memory, Redis, and hybrid modes, including automatic invalidation.
• Reliable message queuing backed by Redis, Azure, and AWS SQS.
• Distributed locking and throttling through the ILockProvider abstraction and CacheLockProvider.
• Pub/sub messaging over Redis, RabbitMQ, Kafka, and Azure Service Bus.
• Background job processing with queue integration, with a job-scheduler topic in the project index.
• A unified file storage API covering disk, S3, Azure Blob, Minio, Aliyun, and SFTP.
• Resilience primitives: retry policies, circuit breakers, and timeouts.

Who uses it and how

• .NET teams building distributed systems that want to code against abstractions rather than a single cloud vendor's SDK.
• Teams running local development and automated tests against the in-memory cache, queue, messaging, storage, and lock implementations, then switching to a real provider at deployment time without changing application code.
• Multi-cloud and hybrid deployments that mix AWS (S3, SQS, SNS), Azure (Storage, Service Bus), Redis, RabbitMQ, Kafka, Minio, Aliyun, and SFTP in the same application.
• Applications already wired through Microsoft.Extensions.DependencyInjection that need caching, queuing, and background jobs registered through the same container.

Getting started

Install the core package with dotnet add package Foundatio. Provider packages such as Foundatio.Redis, Foundatio.AzureStorage, or Foundatio.AWS are added alongside it, and the guide at foundatio.dev covers installation and setup, caching, queues, and the rest of the building blocks.

How it compares

The facts list no paid products that Foundatio replaces, and no directly comparable library is named alongside it. On the evidence here, it stands alone in this registry.

When to use it — and when not to

Foundatio is a library, not a hosted service, so a self-hoster still has to run and operate whichever backing systems are chosen — Redis, RabbitMQ, Kafka, Azure Service Bus, Azure Storage, S3, Minio, Aliyun, or an SFTP server — and the in-memory implementations are intended for local development and testing rather than as a shared production backend. It is not a fit for teams outside the .NET stack, since the abstractions and packages are C#. The licence is a clear Apache-2.0, the repository is active with a recent push and 15 open issues, so the main cost to weigh is operational: someone must own the provider infrastructure underneath.

dotnet add package Foundatio

// Caching
ICacheClient cache = new InMemoryCacheClient();
await cache.SetAsync("user:123", user, TimeSpan.FromMinutes(5));
var cached = await cache.GetAsync<User>("user:123");

// Queuing
IQueue<WorkItem> queue = new InMemoryQueue<WorkItem>();
await queue.EnqueueAsync(new WorkItem { Data = "Hello" });
var entry = await queue.DequeueAsync();

// File Storage
IFileStorage storage = new InMemoryFileStorage();
await storage.SaveFileAsync("docs/readme.txt", "Hello World");

// Distributed Locks
ILockProvider locker = new CacheLockProvider(cache, messageBus);
await using var handle = await locker.AcquireAsync("resource-key");

dotnet nuget add source https://f.feedz.io/foundatio/foundatio/nuget -n foundatio-feedz
dotnet add package Foundatio --prerelease

<configuration>
  <packageSources>
    <add key="foundatio-feedz" value="https://f.feedz.io/foundatio/foundatio/nuget" />
  </packageSources>
  <packageSourceMapping>
    <packageSource key="foundatio-feedz">
      <package pattern="Foundatio.*" />
    </packageSource>
  </packageSourceMapping>
</configuration>