The Croquet Project is a software project that was intended to promote the continued development of the Croquet open-source software development kit to create and deliver collaborative multi-user online applications. Croquet is implemented in Squeak Smalltalk.

Croquet supports communication, collaboration, resource sharing, and synchronous computation among multiple users.

Applications created with the Croquet software development kit can be used to support collaborative data visualization, virtual learning and problem solving environments, 3D wikis, online gaming environments (massively multiplayer online role-playing games (MMORPGs)), and privately maintained or interconnected multiuser virtual environments.

Further development of the technology has also branched into the Open Cobalt and Open Croquet efforts.

The most recent iteration of Croquet is a commercial product developed by Croquet Labs. This version of Croquet runs in a web browser and allows programs to be written in JavaScript or WebAssembly.

Croquet is a software development kit (SDK) for use in developing collaborative virtual world applications.

Applications created using the Croquet SDK are automatically collaborative since application objects in Croquet share a common protocol allowing them to cooperate with each other by employing the principle of replicated computation (synchronization) together with a peer-based messaging protocol. The technology is designed to facilitate such replication between peers, to greatly reduce the overhead needed for widespread deployment of collaborative virtual worlds.

This efficiency, combined with the ability to deploy Croquet-based virtual worlds on consumer-level hardware, makes it possible for developers to deploy large-scale and highly participatory collaborative worlds at very low cost compared with virtual world technologies that are entirely dependent on server-based infrastructures to support the activities of their users.