Kotlin Toolchain 0.12: Multiplatform Library Publishing, Wasm Apps, and More
Article Summary
Joffrey Bion just dropped Kotlin Toolchain 0.12, and it's bringing the multiplatform publishing workflow developers have been waiting for. Plus, Wasm apps just got a whole lot more practical.
JetBrains released Kotlin Toolchain 0.12 with major improvements for multiplatform development. The update expands on the JVM-only library publishing introduced in 0.11, now supporting full Kotlin Multiplatform projects. The release also includes production-ready features tested on klibs.io, a real backend built with JDK 21 and Spring Boot 4.
Key Takeaways
- Multiplatform library publishing now works across JVM, Android, iOS, and Wasm targets
- Wasm apps can be built and run as complete web applications via command line
- Compose Hot Reload now supports MCP server for AI agent interactions
- New project-root-relative paths using // prefix simplify dependency management
- Minimum requirements raised to JDK 17 and Kotlin 2.2.20
Kotlin Toolchain 0.12 makes publishing and building multiplatform libraries significantly easier while adding production-grade Wasm support and AI-friendly developer tools.
About This Article
Maven Central introduced new publication quotas that required JetBrains to cut back on unnecessary file artifacts. Checksum files like .asc.sha1 were taking up space without providing real value.
JetBrains removed the redundant signature checksums and switched to .md5 and .sha1 as the default format. Developers can still publish .sha256 and .sha512 checksums if they enable them through settings.publishing.checksums.
The toolchain now publishes fewer files by default, which means lower quota usage. Developers still have access to extended checksum formats for cryptographic verification when they need them.