Data API Data Formats

MongoDB stores data in a format called BSON, which is similar to a JSON object in structure but supports additional data types and uses a binary encoding. BSON is efficient for computers but is not human readable, so you can't work with it directly.

Instead, the Data API uses two formats to represent data in requests and responses:

• The JSON format uses standard types that any tool can parse and understand. However, JSON cannot represent all BSON types, so JSON responses may lose type information for some fields. For example, BSON has distinct types for 32-bit integers and 64-bit floats, but a JSON response represents both as a number.

• The EJSON format, short for MongoDB Extended JSON, is a superset of standard JSON that uses structured fields to represent BSON data that don't have corresponding JSON types. This fully represents your data but requires your client to understand how to work with EJSON.

You define a single default return type for all generated Data API endpoints and individually for each custom endpoint. Incoming requests can also specify a preferred data format that overrides the default using an Accept header. To learn more, see Choose a Response Data Format.

[ <elements> ]

[ <elements> ]

{
   "$binary": {
      "base64": "e67803a39588be8a95731a21e27d7391",
      "subType": "05"
   }
}

{
   "Subtype": 5,
   "Data": "e67803a39588be8a95731a21e27d7391"
}

{
   "$date": {
      "$numberLong": "1641954803067"
   }
}

"2022-01-12T02:33:23.067Z"

{ "$numberDecimal": "9823.1297" }

"9823.1297"

{ <content> }

{ <content> }

{
   "$numberDouble": "10.5"
}

10.5

{"$numberInt":"10"}

10

{"$numberLong":"50"}

50

{ "$maxKey": 1 }

{}

{ "$minKey": 1 }

{}

{
   "$oid":"5d505646cf6d4fe581014ab2"
}

"5d505646cf6d4fe581014ab2"

{
   "$regularExpression": {
      "pattern":"^H",
      "options":"i"
   }
}

{
   "Pattern": "^H",
   "Options": "i"
}

{
   "$timestamp": {
      "t":1565545664,
      "i":1
    }
}

{
   "T": 1565545664,
   "I": 1
}