Validation
The purpose of creating an API server is to take an input and process it.

JavaScript allows any data to be of any type. Elysia provides a tool to validate data out of the box to ensure that the data is in the correct format.

import { Elysia, t } from 'elysia'

new Elysia()
  .get('/id/:id', ({ params }) => ({
    params: t.Object({
      id: t.Number()
    })
  }))
  .listen(3000)

TypeBox

Elysia.t is a schema builder based on TypeBox that provides type‑safety at runtime, compile‑time, and OpenAPI schema generation from a single source of truth.
Elysia tailors TypeBox for server‑side validation for a seamless experience.

Standard Schema

Elysia also supports Standard Schema, allowing you to use your favorite validation library:

• Zod
• Valibot
• ArkType
• Effect Schema
• Yup
• Joi
• …and more

To use Standard Schema, simply import the schema and provide it to the route handler.

import { Elysia } from 'elysia'
import { z } from 'zod'
import * as v from 'valibot'

new Elysia()
  .get('/id/:id', ({ params, query }) => ({
    params: z.object({
      id: z.number()
    }),
    query: v.object({
      name: v.string()
    })
  }))

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