While at Atari, Crockford wrote another game, Burgers!, for APX[4] and a number of experimental audio/visual demos that were freely distributed.

He was involved[clarification needed] in the development of the programming language E.[8] Crockford was the founder of State Software (also known as Veil Networks) and its CTO from 2001 to 2002.

[9] During his time at State Software, Crockford popularized the JSON data format, based upon existing JavaScript language constructs, as a lightweight alternative to XML.

[citation needed] In 2008 Crockford published a book announcing his discovery that JavaScript, contrary to prevailing opinion, has good parts.

He describes this as "heresy", and as "maybe the first important discovery of the 21st century", noting that it came as a "big surprise to the JavaScript community, and the world at large.

[17][18] According to the GNU project, the licence conflicts with Freedom 0 of the Free Software definition, and although "it may be unenforceable, we cannot presume that", therefore non-free.