Can I use Snapchat in Spanbox?

Yes. Snapchat has a web version, and Spanbox's whole model is that if an app has a web app, you can add it. So you sign into Snapchat inside Spanbox exactly like in a browser and it sits in your unified inbox with the rest, chats from Snapchat for Web. It counts as one of your apps (3 free, unlimited on Pro).

You can even run more than one Snapchat account at once, each in its own isolated session, so a work and a personal Snapchat sit side by side without logging in and out.