What back-end Node.js frameworks do large companies use?

Question

Node.js

Many big companies like Walmart, PayPal, Linkedin, E-bay use Node.js. Do they use frameworks like Express, Sails or others to build the back end, or do they use their own designs?

Answer 1

How did you determine that this is nodejs?
Maybe socket.io or just a websocket server

Answer 2

PayPal use their own layer for Express - kraken.js
Walmart use hapi.js
Here you can read about E-bay
In general, it's very easy to google

Answer 3

Here is a list of users Express
Sails is also powered by express.
I think that big players will build their architecture from small components, thanks npm