Tutorial:Command NBT tags

NBT tags can be specified for entities created with the /summon command. Each tag has the format <tagname>:<value> where <tagname> describes what it does, and <value> is what it applies. Multiple tags are separated by commas. (e.g. {CustomName:'"Bob"', Invulnerable:true}). The contents of List tags are enclosed in square brackets [], while the contents of Compound tags are enclosed in curly brackets {} – note that the entire data tag is itself a Compound tag (All within a set of {}). Tag names are case-sensitive, and white space is ignored. Additionally, some tags which are either true or false are stored as Byte tags (Example: {NoAI:1b})

The player can quickly find data tags (NBT) without the use of external editors by using /data to figure out the data for each entity or block entity. See more about this in the article Commands/data.

See Entity format for the various NBT Tags that are saved for each entity. This page also contains basic information for each NBT Tag.