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Hazelcast vs ScaleOut StateServer

Hazelcast: A Java in-memory data grid and stream processor that embeds in your app or runs as a cluster. ScaleOut StateServer: Commercial in-memory data grid for .NET and Java with parallel query, Redis support and in-cache code.

key differences

  • Licensing: Hazelcast is open source (permissive) (Apache 2.0 (Community); Hazelcast Community License for some modules); ScaleOut StateServer is proprietary (Proprietary).
  • Only Hazelcast has transactions, joins, vector search, json, change data capture.
  • Hazelcast can run embedded in your application process.

choose hazelcast for

  • +Shared low-latency state for microservices
  • +Fraud detection and payment stream processing
  • +Web session clustering for Java app servers
  • +Distributed caching in front of RDBMS

best at · Cache, Sessions, Streaming

choose scaleout-stateserver for

  • +Distributed session state for ASP.NET and Java web farms
  • +Low-latency shared object cache for .NET services
  • +Real-time analytics and digital twins over fast-changing data
  • +Replacing self-managed Redis in Windows-centric shops

best at · Cache, Sessions, Real-time analytics

HazelcastA Java in-memory data grid and stream processor that embeds in your app or runs as a cluster.
ScaleOut StateServerCommercial in-memory data grid for .NET and Java with parallel query, Redis support and in-cache code.
overview
Primary model
Key-Value
Key-Value
Also supports
Document, Vector
Document
Type
Database engine
Database engine
Status
Active
Active
Developer
Hazelcast, Inc.
ScaleOut Software, Inc.
First release
2008
2005
Latest version
5.7.0 (May 12, 2026)
6 (Sep 2025)
License
Open source (permissive)Apache 2.0 (Community); Hazelcast Community License for some modules
ProprietaryProprietary
Free tier
✓
—
popularity
WhichDB Score
33.5
0.0
Rank
#63
#806
GitHub stars
6.6K
–
Stack Overflow questions
2.9K
–
scale & guarantees
Comfortable data size
Medium (≤ 10 TB)
Medium (≤ 10 TB)
Horizontal scaling
Native
Native
Multi-region
Active active
Read replicas
ACID
Limited
Limited
Consistency
Eventual, Strong
Strong
Schema
Flexible
Schemaless
Architecture
In memory, Distributed, Embedded, Client server
Distributed, In memory
deployment
Self-hosted
✓
✓
Vendor-managed cloud
—
—
Serverless
—
—
Embedded
✓
—
Edge
—
—
Clouds
AWS, Google Cloud, Azure
–
capabilities
Transactions
✓
—
Joins
✓
—
Secondary indexes
✓
✓
Full-text search
—
—
Vector search
✓
—
Geospatial
—
—
JSON
✓
—
Change data capture
✓
—
Triggers
—
—
Stored procedures
✓
—
Materialized views
—
—
TTL / expiry
✓
✓
Pub/Sub
✓
✓
Columnar storage
—
—
In-memory
✓
✓
Durable persistence
✓
—
Compression
✓
—
Encryption at rest
—
—
Role-based access
—
—
Time travel
—
—
Branching
—
—
Online schema changes
—
—
Streaming ingest
✓
—
Offline sync
—
—
Runs in WebAssembly
—
—
interfaces
Query languages
SQL, Predicate API, Jet Pipeline API
LINQ, Java/C++ filter APIs, Redis commands
Client languages
Java, C#, C++, Python, JavaScript, Go
C#, Java, C, C++
Best for
Cache, Sessions, Streaming, Real-time analytics
Cache, Sessions, Real-time analytics, Pub/Sub
Add more to this comparisonNot sure either fits? Try smart match

Hazelcast vs ScaleOut StateServer: FAQ

What is the difference between Hazelcast and ScaleOut StateServer?

Hazelcast: A Java in-memory data grid and stream processor that embeds in your app or runs as a cluster. ScaleOut StateServer: Commercial in-memory data grid for .NET and Java with parallel query, Redis support and in-cache code. Licensing: Hazelcast is open source (permissive) (Apache 2.0 (Community); Hazelcast Community License for some modules); ScaleOut StateServer is proprietary (Proprietary). Only Hazelcast has transactions, joins, vector search, json, change data capture. Hazelcast can run embedded in your application process.

When should I choose Hazelcast over ScaleOut StateServer?

Choose Hazelcast for shared low-latency state for microservices; fraud detection and payment stream processing; and web session clustering for Java app servers. Choose ScaleOut StateServer for distributed session state for ASP.NET and Java web farms; low-latency shared object cache for .NET services; and real-time analytics and digital twins over fast-changing data.

Is Hazelcast or ScaleOut StateServer more popular?

Hazelcast ranks #63 on the WhichDB Score (33.5/100) and ScaleOut StateServer ranks #806 (0.0/100). Popularity is not fit: check the requirements that matter for your project.

Are Hazelcast and ScaleOut StateServer open source?

Yes. Hazelcast is open source. License: Apache 2.0 (Community); Hazelcast Community License for some modules. No. ScaleOut StateServer is proprietary, closed-source software.