How to validate URL param with AJV in Fastify?

I'm trying to validate the URL param verificationToken, the issue is that the reply is always Verification token is required. as if the token is not provided in the URL.

export const UserActivationSchema = {
    schema : {
       querystring: {
          type                : 'object',
          required            : [ 'verificationToken' ],
          additionalProperties: false,
          properties          : {
             verificationToken: {
                type: 'string'
             },
          },
          errorMessage        : {
             properties: {
                verificationToken: 'Verification token is required.'
             },
             required: 'Verification token is required.'
          }
       },
    },
    handler: activateEmail,
}

The route:

fastify.get( '/activate/:verificationToken', UserActivationSchema );

I need to verify the verificationToken it is a string and provided in the URL.

Any idea how to fix this?

I'm trying to verify the verificationToken is a string and provided in the URL.

The url in that syntax defines a path parameter and it is not a query string parameter.

You must change the schema property querystring to params.