Build Tools API: a stable interface for the Kotlin compiler | Wojtek Kalicinski

Recording brought to you by American Express. https://americanexpress.io/kotlin-jobs The Kotlin compiler is the heart of the Kotlin ecosystem, but integrating it reliably into custom build systems, IDEs, or other tools has long presented challenges. Historically, interactions often relied on command-line interfaces (CLI) or internal, unstable APIs, making support for features like incremental compilation and multiplatform projects (KMP) difficult to maintain. Enter the Kotlin Build Tools API (BTA): a new, stable, and programmatic interface designed to simplify these integrations. BTA offers a consistent way to perform common compiler operations, starting with compiling Kotlin source files for the JVM platform - complete with full support for daemon/in-process modes and crucial features like incremental compilation, with other platforms and KMP to follow. In this talk, aimed at engineers building tools that rely on Kotlin compilation, we will delve into the historical pain points of compiler interaction, introduce BTA, and explain the architectural guarantees it provides. Attendees will receive a detailed technical overview of how to work with the API - from initialization to executing operations - and see real-world examples demonstrating how tools like the Kotlin Gradle Plugin (KGP) and Maven are already leveraging BTA for robust JVM compilation. Join us to learn how BTA provides a stable foundation, allowing you to build the next generation of powerful Kotlin tools.