Standard Schema Validation

Standard Schema is a convention supported by modern validation libraries that implements a common interface for defining and validating data structures. It’s supported by libraries like Zod 4 , Arktype , Valibot , Effect Schema and many others. Check full list of libraries that implement Standard Schema at the original repository .

Vovk.ts provides a simple createStandardValidation function that creates a custom validation library that uses Standard Schema. The only option of this function is toJSONSchema function that defines how to convert the models to JSON Schema format.

Arktype example

Create withArk somewhere in your codebase:

src/lib/withArk.ts


import type { type } from 'arktype';
import { createStandardValidation } from 'vovk';
 
export const withArk = createStandardValidation({
  toJSONSchema: (model: type) => model.toJsonSchema(),
});

Then use it in your controller:

src/modules/user/UserController.ts


import { prefix, post, openapi } from 'vovk';
import { type } from 'arktype';
import { withArk } from '@/lib/withArk';
 
@prefix('users')
export default class UserController {
  @openapi({
    summary: 'Update user (Arktype)',
    description: 'Update user by ID with Arktype validation',
  })
  @post('{id}')
  static updateUser = withArk({
    body: type({
      name: type('string').describe('User full name'),
      age: type('0 < number < 120').describe('User age'),
      email: type('string.email').describe('User email'),
    }),
    params: type({
      id: type('string.uuid').describe('User ID'),
    }),
    query: type({
      notify: type('"email" | "push" | "none"').describe('Notification type'),
    }),
    output: type({
      success: type('boolean').describe('Success status'),
    }),
    async handle(req, { id }) {
      const { name, age } = await req.json();
      const notify = req.nextUrl.searchParams.get('notify');
 
      // do something with the data
      console.log(`Updating user ${id}:`, { name, age, notify });
      return {
        success: true,
      };
    },
  });
}

Valibot example

Create withValibot somewhere in your codebase:

src/lib/withValibot.ts


import { createStandardValidation, type KnownAny } from 'vovk';
import { toJsonSchema } from '@valibot/to-json-schema';
import type { BaseSchema } from 'valibot';
 
export const withValibot = createStandardValidation({
  toJSONSchema: (model: BaseSchema<KnownAny, KnownAny, KnownAny>) => toJsonSchema(model),
});

Then use it in your controller:

src/modules/user/UserController.ts


import { prefix, post, openapi } from 'vovk';
import * as v from 'valibot';
import { withValibot } from '@/lib/withValibot';
 
@prefix('users')
export default class UserController {
  @openapi({
    summary: 'Update user (Valibot)',
    description: 'Update user by ID with Valibot validation',
  })
  @post('{id}')
  static updateUser = withValibot({
    body: v.pipe(
      v.object({
        name: v.pipe(v.string(), v.description('User full name')),
        age: v.pipe(v.number(), v.minValue(0), v.maxValue(120), v.description('User age')),
        email: v.pipe(v.string(), v.email(), v.description('User email')),
      }),
      v.description('User object')
    ),
    params: v.object({
      id: v.pipe(v.string(), v.uuid(), v.description('User ID')),
    }),
    query: v.object({
      notify: v.pipe(v.picklist(['email', 'push', 'none']), v.description('Notification type')),
    }),
    output: v.pipe(
      v.object({
        success: v.pipe(v.boolean(), v.description('Success status')),
      }),
      v.description('Response object')
    ),
    async handle(req, { id }) {
      const { name, age } = await req.json();
      const notify = req.nextUrl.searchParams.get('notify');
 
      // do something with the data
      console.log(`Updating user ${id}:`, { name, age, notify });
      return {
        success: true,
      };
    },
  });
}

All other libraries are implemented in a similar way. The only difference might be different toJSONSchema implementations. Once standard-schema/issues/21 is resolved, the requirement to use createStandardValidation will probably become obsolete in most of cases.

Vovk.ts originally planned to support definite set of validation libraries, but with Standard Schema it doesn’t make sense to create a separate package for each library anymore.