[cygned]

Others will talk about the benefits, so let me give you a few gotchas from us:

1. It does not replace type checks at runtime (in integration layers)

2. Compilation and startup (in backend land) is slow

3. Some tooling seemingly caches (webpack? ts-node?), we regularly run into situations where rebuilding locally works but then building for prod fails with type errors

[eropple]

1. You can deal with this with stuff like io-ts or runtypes. I strongly recommend either, though I use runtypes myself. Defining your objects in runtypes and having it implicitly return types for use elsewhere in your application is awesome, and it even works with branded types.

2. Yes and no. It's not the fastest build out there but if you've enabled incremental builds it's quite quick unless you're touching heavily related-to code (libraries that are imported all over the place). If that's not fast enough for you, I've seen people having very good success with `swc`.

3. I can't speak to webpack, but ts-node shouldn't be caching anything last I looked at it.

[wereHamster]

2. esbuild has support for TS (it strips the type annotations out during build), and is plenty fast (compared to webpack, rollup etc). So bundling itself should never be an issue. The other aspect is type checking. If you want TS to type check your project, then yes it takes a bit of time. But that's no different than running tests. Of course running those will take some time. Once the project is bundled, the startup time should not be affected at all, it's all JS anyways.