Hazelcast IMDG Standard Support has expired. Extended support for version 4.1 ends in April 2024. Extended support for version 4.2 ends in September 2024.

We recommend that you try Hazelcast Platform.

In Hazelcast Platform, we’ve combined the in-memory storage of IMDG with the stream processing power of Jet. Find out more in our Platform documentation.

The following topics are a good place to start:

Hazelcast IMDG Reference Manual 4.2.8

Welcome to the Hazelcast IMDG (In-Memory Data Grid) Reference Manual. This manual includes concepts, instructions and examples to guide you on how to use Hazelcast and build Hazelcast IMDG applications.

This reference manual mostly talks about the Hazelcast member and clients in Java language. Although, the core of Hazelcast IMDG is based on the Java programming language, it has the following clients and programming language APIs.

  • Java

  • .NET

  • C++

  • Node.js

  • Python

  • Go

We recommend you to learn the basics of Hazelcast IMDG using this manual first. Then, you can always get the client related resources/links in the Clients chapter.


This Reference Manual covers all editions of Hazelcast IMDG. Throughout this manual:

  • Hazelcast or Hazelcast IMDG refers to the open source edition of Hazelcast in-memory data grid middleware. Hazelcast is also the name of the company (Hazelcast, Inc.) providing the Hazelcast product.

  • Hazelcast IMDG Pro is a commercially licensed edition of Hazelcast IMDG which provides CP Sub-system Persistence, Hot Restart Persistence, Unlimited Members on Hazelcast Management Center (This is restricted to 3 members on the freely available but unlicensed version of Management Center) & 24/7 support.

  • Hazelcast IMDG Enterprise is a commercially licensed edition of Hazelcast IMDG which provides all the features of the Pro Edition, plus High-Density Memory Store, Security Suite (RBAC, TLS, Mutual Auth, Client Certificates), WAN Replication (Sync data between two geo-replicated clusters), Blue/Green Deployments, Rolling Upgrades, Automatic Disaster Recovery for Clients & 24/7 supports.

The Pro and Enterprise editions offer all the features of the open source edition.


Hazelcast IMDG and Hazelcast Reference Manual are free and provided under the Apache License, Version 2.0. Hazelcast IMDG Pro and Enterprise are commercially licensed by Hazelcast, Inc.

For more detailed information on licensing, see the License Questions appendix.


Hazelcast is a registered trademark of Hazelcast, Inc. All other trademarks in this manual are held by their respective owners.


Hazelcast provides two types of support: community and customer.

Community support is for every Hazelcast IMDG user. You can use the following channels for this purpose:

Customer support is for the paying Hazelcast IMDG customers. See hazelcast.com for the support options.

Release Notes

See the Release Notes document for the new features, enhancements and fixes performed for each Hazelcast IMDG release.


You can contribute to the Hazelcast IMDG code, report a bug, or request an enhancement. See the following resources:

  • Developing with Git: Document that explains the branch mechanism of Hazelcast and how to request changes.

  • Hazelcast on GitHub: Hazelcast repository where the code is developed, issues and pull requests are managed.


Hazelcast partners with leading hardware and software technologies, system integrators, resellers and OEMs including Amazon Web Services, Vert.x, Azul Systems, C2B2. See the Partners page for the full list of and information on our partners.