Hoi hoi! 👋

I'm nyaomaru, a frontend engineer and OSS developer working mostly with TypeScript.

When we need runtime validation in TypeScript, the conversation often turns into this 👇

"Which library should I use?"

Zod ?

Valibot ?

ArkType ?

typia ?

Or maybe, just write a type guard?

I maintain is-kit , so I think about this boundary quite a lot.

And recently I started wondering

Are we comparing libraries that are actually solving the same problem?

For example, if all I want is this

if ( isUser ( input )) { input . name ; }

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do I really need a schema system?

But if I want:

structured validation errors

transformations

parsing

schema metadata

framework integrations

then a small boolean guard is probably not enough either.

So instead of asking "Which validator is best?" , I tried a different comparison.

I implemented the same User validation with:

a handwritten guard with a TypeScript…