Setup

typia is a compile-time transformer, so your build has to run through the TypeScript 7 transformer path. Install typia, typescript, and ttsc; then build with ttsc or execute TypeScript directly with ttsx.

Install

npm i typia
npm i -D ttsc typescript

pnpm i typia
pnpm i -D ttsc typescript

yarn add typia
yarn add -D ttsc typescript

bun add typia
bun add -d ttsc typescript

Keep the TypeScript project strict:

{
  "compilerOptions": {
    "strict": true
  }
}

Build

Use ttsc where you would normally run a TypeScript compiler:

npx ttsc
npx ttsc --noEmit
npx ttsc --watch

pnpm ttsc
pnpm ttsc --noEmit
pnpm ttsc --watch

yarn ttsc
yarn ttsc --noEmit
yarn ttsc --watch

bun ttsc
bun ttsc --noEmit
bun ttsc --watch

Execute Without Building

Use ttsx instead of runners that strip TypeScript before typia can transform it:

npx ttsx src/index.ts

pnpm ttsx src/index.ts

yarn ttsx src/index.ts

bun ttsx src/index.ts

Bundlers

Bundlers such as Vite, Next.js, Rollup, esbuild, Webpack, Rspack, Farm, and Bun run their own TypeScript pipeline. Install @ttsc/unplugin and add the matching plugin to the bundler config.

npm i -D @ttsc/unplugin

import ttsc from "@ttsc/unplugin/vite";
import { defineConfig } from "vite";
 
export default defineConfig({
  plugins: [ttsc()],
});

If the bundler should use a config other than tsconfig.json, pass project:

import ttsc from "@ttsc/unplugin/vite";
import { defineConfig } from "vite";
 
export default defineConfig({
  plugins: [
    ttsc({
      project: "tsconfig.bundle.json",
    }),
  ],
});

Transform Options

Most projects do not need this section. Add compilerOptions.plugins only when you want to change an optional typia transform flag:

{
  "compilerOptions": {
    "strict": true,
    "strictNullChecks": true,
    "plugins": [
      {
        "transform": "typia/lib/transform",
        "functional": true,
        "numeric": true,
        "finite": true
      }
    ]
  }
}

Verify

Drop this into your project and run it through the same command you use for the application:

import typia from "typia";
 
console.log(typia.is<{ id: string }>({ id: "ok" }));
// true

If it prints true, the transform ran. If it throws Error on typia.<method>(): no transform has been configured., the command bypassed ttsc, ttsx, or @ttsc/unplugin.

Where to go next

• First validator after setup: is, assert, validate
• Why typia needs a transform: Pure TypeScript
• Bundled framework recipes: Utilization Cases