Currently WhatsApp group size limit is still only 256 users. What if you wanted to join a full group? WAJoin will let you join full WhatsApp groups by waiting for the exact moment another user exits the group and then automatically replacing him. WAJoin works with browser automation using Puppeteer and Chome Dev Tools.

http://ec2-3-131-96-248.us-east-2.compute.amazonaws.com/

git clone https://github.com/danzilberdan/WAJoin.git
cd WAJoin
npm i

node index.js

This will start a web server in port 3000.