I've personally been with the company for almost a year, working on "Mission Control", an internal web app for managing the satellites and make life easier on our "Spaceship Captains" -- the operators who manage them. This is definitely one of the most interesting and fun roles I've had in my career (and I've had a few).
Python (Flask, Django) and Javascript (React, Backbone) are used heavily in the web projects. We of course have systems programming to do for the onboard software. Plenty of other interesting work from the satellite design and various subsystems, manufacturing, georectification of images, image corrections, and heaps of possibilities with a supremely interesting dataset that we're growing.
Some gigs are onsite only, others may be available to remote workers.
Full list of jobs at https://www.planet.com/careers/#openings