What is NCache?

NCache is an in-memory distributed cache designed for .NET, Java, Python, and Node.js applications. It is developed and maintained by Alachisoft, and it allows applications to store frequently accessed data in memory across multiple servers, reducing the need to access slower data sources, such as databases or external services.

NCache runs as a separate caching tier in the application architecture and is accessed through client APIs that provide support for key-value storage, querying, messaging, and cache management. NCache is natively built for .NET and supports deployment on both Windows and Linux environments.

Overview

As application load increases, repeated access to databases and backend data sources can become a bottleneck. NCache addresses this by introducing a distributed in-memory caching tier that stores frequently accessed data and reduces direct interaction with the data source.

NCache uses a clustered architecture where cache servers are grouped into a cache cluster. Data is distributed across cache nodes, and applications access the cache through client APIs. As demand increases, cache servers can be added to the cluster to increase capacity and throughput without requiring application changes.

The primary benefits of using NCache are:

  • Performance: NCache improves application response time by storing data in-memory on cache servers, reducing the need to access slower backend data sources.

  • Scalability: NCache supports dynamic clustering, allowing cache servers to be added or removed at runtime. Data is automatically distributed across the cluster to handle increased load.

  • High Availability: NCache provides multiple caching topologies (such as Partitioned and Partitioned-Replica) that ensure cache availability and fault tolerance in case of node failures.

  • Consistency: NCache provides expiration and eviction policies, as well as dependency features (such as database dependencies), to keep cached data synchronized with the data source.

NCache integrates with .NET applications and supports frameworks such as ASP.NET Core, allowing applications to use caching without significant architectural changes.

Key Use Cases

The following list describes the most common use cases and what NCache provides in each context.

  • Application Data Caching: Cache frequently accessed data such as database query results, domain objects, and reference data to reduce database round-trips and improve response time.
  • ASP.NET & ASP.NET Core Session Storage: Store user session state in a distributed cache to support load-balanced web applications and avoid reliance on a centralized session store.
  • Pub/Sub Messaging: Use NCache messaging features to publish and subscribe to events across distributed applications. Supports topic-based messaging and event notifications.

Editions and Licensing

NCache is available in multiple editions to support different deployment and usage requirements. Each edition provides a different set of capabilities, allowing teams to choose based on application scale, performance needs, and operational requirements.

NCache Enterprise

A commercial edition that provides the complete NCache feature set for production environments. It supports advanced distributed caching capabilities, multiple caching topologies, Pub/Sub messaging, SQL and LINQ querying, and integrations with .NET, Java, Python, and Node.js platforms. NCache Enterprise is designed for mission-critical applications that require high availability, scalability, and access to professional support and maintenance.

NCache Open Source

A free, open-source edition of NCache that provides a fully functional distributed caching platform for modern applications. It enables fast, in-memory data access with essential distributed caching capabilities, including basic cache operations and cross-platform support. NCache Open Source offers an accessible way to build responsive applications and explore distributed caching without licensing cost.

Note

For a detailed feature comparison across editions, refer to the NCache Edition Comparison page.

Licensing Models

NCache licensing is based on how cache servers and clients are used:

  • Cache Server: Licensed for machines running the NCache service. Required for production cluster nodes.

  • Remote Client: Used by application servers connecting to the cache cluster. Licensing depends on the selected model.

  • Dev/QA: Intended for development and non-production environments, with limitations suitable for testing purposes.

Note

For detailed information on licensing models, refer to the Licensing Model page.

See Also

Installation Guide
Getting Started Guide
Developer's Guide
Administrator's Guide