TypeScript compilation can slow down due to large codebases or complex type definitions. You can improve performance by using `incremental` compilation, optimizing `tsconfig.json`, and splitting the project into smaller modules.

As TypeScript projects grow in size and complexity, compilation speed can become an issue. Some of the main culprits behind slow compilation times include large or deeply nested type definitions, extensive use of any, and inefficient configurations in tsconfig.json. To address this, enabling incremental compilation is one solution, which caches previous build information, speeding up subsequent builds. Additionally, using tsc --build mode with project references allows you to split large projects into smaller, independently compiled modules. Removing unnecessary strict type checks, optimizing include and exclude paths in tsconfig.json, and keeping dependencies up to date also help in reducing build times. For projects with complex types, precomputing some types or leveraging libraries like typebox can further improve performance.