Open source

Open source means the people who wrote a program publish its code for everyone. You can read how it works, fix a bug yourself or build your own version on top of it.

For robots this matters because you are not stuck with what the maker shipped. If a company releases its robot software as open source, hobbyists can teach the robot new tricks and share them with each other.

Open source does not always mean free hardware. You may still pay for the robot itself, as with a $399 walking robot whose software anyone can download.