JetBrains open sources KotlinLLM runtime code generator

Experimental IntelliJ IDEA plugin for Kotlin/JVM projects is used to delegate runtime logic to an LLM from Kotlin code. KotlinLLM, a research prototype for delegating runtime logic to a large language model (LLM) from Kotlin code, is now going open source and public, JetBrains announced. Revealed July 28, KotlinLLM is an IntelliJ IDEA plugin prototype for experimenting with LLM-driven “Smart macros” in Kotlin, enabling code generation, runtime updates, and hot-reloading. In software engineering, LLMs are commonly used during development for code completion, code generation, and program comprehension, JetBrains noted, but using an LLM at run time of a compiled application is much less common. The existing options for doing this have the following trade-offs, according to JetBrains: Direct runtime delegation is slow, non-deterministic, and costly, and makes the application depend on an LLM service at run time. External agent workflows keep the generated logic outside the codebase, where it is harder to review, test, and ship. Most prior work (byLLM, nightjar, Healer) targets interpreted languages like Python, not a compiled, statically typed language like Kotlin. KotlinLLM addresses these limitations in three ways, JetBrains said: The call site shows that a feature is LLM-backed, so it is visible in code review. Generated behavior is saved as an ordinary Kotlin source, not kept only in the runtime session. It can be committed, reviewed, tested, and distributed like any other code. Once generated, the code runs as plain Kotlin without the plugin. For scenarios that are already covered, there is no further LLM call, so no added latency or cost, and the result is reproducible. KotlinLLM is open source under Apache License 2.0. The repository contains the KotlinLLM IntelliJ IDEA plugin, the Smart macro API, and example projects. Paul Krill is editor at large at InfoWorld. Paul has been covering computer technology as a news and feature reporter for more than 35 years, including 30 years at InfoWorld. He has specialized in coverage of software development tools and technologies since the 1990s, and he continues to lead InfoWorld’s news coverage of software development platforms including Java and .NET and programming languages including JavaScript, TypeScript, PHP, Python, Ruby, Rust, and Go. Long trusted as a reporter who prioritizes accuracy, integrity, and the best interests of readers, Paul is sought out by technology companies and industry organizations who want to reach InfoWorld’s audience of software developers and other information technology professionals. Paul has won a “Best Technology News Coverage” award from IDG. More from this author Visual Studio Code 1.131 zeroes in on subagents Jul 29, 2026 2 minsJDK 27: The new features of Java 27 Jul 29, 2026 4 minsAnthropic releases ‘more efficient’ Claude Opus 5 Jul 26, 2026 2 minsVisual Studio Code 1.130 dresses up Agents window Jul 23, 2026 2 minsG# language for .NET borrows from Go, Kotlin, and Swift Jul 22, 2026 2 minsGitLab previews auto-remediation of vulnerable dependencies Jul 22, 2026 2 minsVisual Studio Code 1.129 introduces dedicated agent host Jul 21, 2026 3 mins‘The Java Story’ recounts the rise, fall, and rise again of Java Jul 21, 2026 2 mins Show me more