Kryo is an open-source Java serialization framework for storing objects in files or databases and transferring them over a network. It processes object graphs and supports automatic deep and shallow copying and cloning. Serializers control how types are read and written, and can be replaced to suit an application. Installation instructions and code examples are available in the project documentation.
| Author: | Nathan Sweet |
| License: | Open Source |
| Price: | FREE |
| Released: | Oct 7, 2026 |
| File size: | 2.20 MB |
| Downloads: | 32 |
| Keywords: | serialization, java serialization api, Kryo, API, serialize java objects, object graph serialization, java serialization framework, Kryo free download, framework, download Kryo, Java serialization, java deep copy library, object graph, java object persistence, serialization framework |
| Author URL: | https://github.com/EsotericSoftware/kryo |
Kryo is an open-source serialization framework for Java applications that need to turn objects into data and reconstruct them later. It is intended for developers working with persistence, communication between processes, or other systems where Java objects must be stored or transferred. The framework handles object graphs, allowing related objects to be serialized together, and also provides automatic deep and shallow copying and cloning for workflows that need duplicates rather than persistent output.
Serialization can be used to write objects to files or databases, or to send them across a network. Kryo supplies an API for these operations, while serializers determine how particular types of data are read and written. The framework does not impose a schema or dictate a single representation for every type. Developers can use the serializers provided for their needs or replace them with alternatives when an application requires different handling. This separation gives projects control over how their data is encoded and decoded.
The same object-processing capabilities support copying and cloning. A shallow copy duplicates an object without recursively duplicating everything it references, while a deep copy also processes referenced objects. These options are useful in different situations, such as creating an independent working copy or preserving references within a larger object graph. Kryo is therefore relevant not only to storage and transport, but also to Java applications that need controlled object duplication.
Kryo is suited to application developers building persistence layers, networked software, and other Java systems that exchange or retain structured objects. Because it does not manage application schemas, projects remain responsible for choosing compatible serializers and handling changes in their own data formats. The library uses major version changes when serialization compatibility is broken, and minor version changes when binary or source compatibility of its public API is broken. Installation guidance is available for projects using Maven as well as those managing dependencies without it, and the project's user guide provides explanations and code examples.
The framework is open source and is aimed at Java development rather than use as a standalone desktop application. Its project documentation is the practical starting point for installation and integration, including examples of using Kryo in different projects. The Windows download is intended for developers looking for the library files; integrating it into an application requires a Java development environment and the relevant project setup.