Is it legal to use a PSN code generator?

The use of software to generate, modify or obtain codes for redemption on the Playstation Service Network is not legal for Playstation users, according to Sony. Obtaining and using codes to circumvent the application store and programmed barriers that prohibit theft are against Sony's community code of conduct.

Redeeming illegally obtained codes can hinder business operations and harm developers and publishers of video game content on PSN, and in some cases results in discontinued support for games or the platform, explains Sony. Breaking the rules and infringing on the community code of conduct can result in disciplinary action including account suspension and the hardware being banned from the network.