Is Perplexity available in Spanbox?

Yes. Perplexity 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 Perplexity inside Spanbox exactly like in a browser and it sits in your unified inbox with the rest, for quick answers beside your inbox. It counts as one of your apps (3 free, unlimited on Pro).