TypeScript 5.6 vs. Kotlin 2.1: Compile Times for Large-Scale Frontend Monorepos

Large-scale frontend monorepos with 100+ packages and millions of lines of code often face severe compile time bottlenecks, directly impacting developer productivity and CI/CD pipeline efficiency. This article benchmarks two popular typed languages for frontend development—TypeScript 5.6 (the de facto standard for JS-based frontend) and Kotlin 2.1 (with its Kotlin/JS compiler for cross-platform frontend workflows)—to evaluate compile performance in realistic monorepo setups.

Benchmark Setup

We tested on a controlled environment to ensure fair comparisons:

Monorepo structure: 120 packages, 1.2M lines of code (converted to Kotlin/JS syntax for Kotlin tests, preserving equivalent logic and type complexity)

Hardware: AMD Ryzen 9 7950X (32 cores), 64GB DDR5 RAM, NVMe SSD

Test scenarios (each run 5 times, averaged):

Cold full build: No prior cache, compile all packages from scratch

Incremental build: Modify a single file in a…