Magento2 : How to setup PWA in Localhost?

alright you just need to update .env for variable CUSTOM_ORIGIN_EXACT_DOMAIN

 # vi .env
 # update value 
   CUSTOM_ORIGIN_EXACT_DOMAIN="pwa.dev"
 # now run 
   yarn buildpack create-custom-origin ./
 # Acquired custom hostname and SSL cert for pwa.dev. Development server will run on port 8626 and staging server will run on port 9626
 # Run server again
   yarn watch 
 # Project is running at https://pwa.dev:8626/

Official pwa setup guide And Create custom origin guide

let me know if this works

Magento 2.3.1 PWA setup on local server

Requirements:

Nodejs > 10.14.1 installed

yarn > 1.13.0 installed

A running instance of Magento 2.3.1 or above

Steps to Setup PWA in local server

• Clone the PWA studio repository in the development environment: git clone https://github.com/magento-research/pwa-studio.git

• Install yarn from your pwa-studio root directory yarn install

• Create the .env file at location pwa-studiopackagesvenia-concept using following command

  MAGENTO_BACKEND_URL="https://master-7rqtwti-mfwmkrjfqvbjk.us-4.magentosite.cloud/" yarn buildpack create-env-file packages/venia-concept

• Set the MAGENTO_BACKEND_URL. You can use the value provided in the example command or use your Magento instance url. This URL points to a cloud instance of Magento 2.3.1 with the Venia sample data installed.

• Generate SSL Certificate using yarn buildpack create-custom-origin packages/venia-concept

• Build artifacts for Venia using the following command from the project root directory

  yarn run build

• Start the Venia development environment using the following command

  yarn run watch:venia

• You can browse your PWA Magneto application at https://magento-venia-concept-j2188.local.pwadev:8119

Hope this solution will work for you.

If you checked the steps and results from PWA documentation: https://magento-research.github.io/pwa-studio/venia-pwa-concept/setup/ you will see that actually you got the local dev URL for your PWA development server. Check to add that URL to your hosts file in case that is not working for your setup.