Gosu (programming language)

Gosu
DeveloperGuidewire and open source contributors
Stable release
1.18.4  / 15 May 2025 (15 May 2025)
Typing disciplinestatic
PlatformExecute on the Java Virtual Machine, statically and dynamically compiles to bytecode
OSany supporting JVM
LicenseApache License 2.0
Filename extensions.gs, .gsp, .gst, .gsx
Websitegosu-lang.github.io
Influenced by
Java, C#
Influenced
Kotlin

Gosu is a statically typed general-purpose programming language that runs on the Java Virtual Machine. Its influences include Java, C#, and ECMAScript. Development of Gosu began in 2002 internally for Guidewire Software, and the language saw its first community release in 2010 under the Apache 2 license.

Gosu can serve as a scripting language, having free-form Program types (.gsp files) for scripting as well as statically verified Template files (.gst files). Gosu can optionally execute these and all other types directly from source without precompilation, which also distinguishes it from other static languages.