Read a JSON file with Import:

If the file name’s extension is not “.json”, specify the file’s type explicitly:

Read a UBJSON file with Import:

If the file name’s extension is not “.ubj”, specify the file’s type explicitly:

• UBJSON is a binary format that imitates and is compatible with JSON. It is more compact and more efficient than JSON, but is not human readable.

Read an ExpressionJSON file with Import:

• ExpressionJSON provides lossless round-tripping of Wolfram Language expressions to and from JSON.