Which one is lighter, JSON or BSON?

Question

I have written code to serialize objects to JSON and BSON. According to my output, the BSON produced is greater in size than the JSON. Is this expected?

From my

Answer 1

The property "foo":"bar" consumes 11 bytes in UTF-8 encoded JSON. In BSON it consumes 13:

bytes       description
============================================
1           entry type value \x02
3           "foo"
1           NUL \x00
4           int32 string length (4 -- includes the NUL)
3           "bar"
1           NUL \x00

There are many cases in which JSON will be more compact.