Json objects, every object has a type. Other fields decend from the type.

A type of measure indicates a datapoint for a thing that varies over time. For example, weight, body-fat percentage.

A thing field is required, indicating what is measured. The thing strictly maps to information about units (for example)

A source field is optional, may indicate the device or system used to capture this measure.

A timestamp field is required, numeric UTC epoch time in seconds (eg, as output by date +%s)

A scope field is optional, this can be used to indicate the measure should be applied to that scope, for example "day". If I'm capturing my subjective experience of the last day, I'll specify a scope of "day".

A timezone field is optional, as a UTC offset in hours. For example, PDT would be -7. Timezone should be specified if using a scope of "day"

A type of event indicates a thing that happend, for example. I drank a cup of coffee, I urinated.

action is a required field. This is what happend. It is a strict mapping to to a table of actions. Examples may include "coffee" or "pee".

quantity is an optional field. Some actions may require it. Any action that requires a quantity defines it's units and meaning

duration is an optional field. Some actions may require it.

timestamp is a required field. UTC epoch seconds.

timezone is optional

A type of update reflects a state change. Examples might include: "I went to sleep", changing my state from awake to asleep. Or: "I started a low-carb diet".

timestamp required

property is required. This is the thing that has a changing state. It defines the units and meaning of the state field.

state is required, this must be a number. For binary states 1 means on and 0 means off. For example "property":"sleep", "state":0 means I woke up. It could also be the current dosage of a drug that is used regularly.