Validates the value to ensure it is not inside an array of provided values.

There is no rule. We encourage you to use the enum schema type as it provides better static type safety.

username: schema.string([
rules.notIn(['admin', 'super', 'root'])

Providing values as a ref

If your list options relies on the runtime values and you are using schema caching, then you must move them to the refs.

Following is example of defining options via refs.

import { schema } from '@ioc:Adonis/Core/Validator'
import { HttpContextContract } from '@ioc:Adonis/Core/HttpContext'
export default class CreateUserValidator {
constructor(protected ctx: HttpContextContract) {}
public refs = schema.refs({
unallowedValues: getValuesFromSomewhere(),
public schema = schema.create({
username: schema.string([
public cacheKey = this.ctx.routeKey

Custom messages options

The notIn validation rule passes the values array as the only option to custom messages.

'notIn': 'The {{ field }} value cannot be one of {{ options.values }}',