MongoDB Extended JSON (EJSON) Converter

More information about MongoDB Extended JSON

JSON has no way to express MongoDB's rich BSON types (ObjectId, Date, 64-bit integers, Decimal128, and more). Extended JSON (EJSON) solves that by wrapping those values in special keys so no type information is lost when you export or move data as text.

The three representations

• Canonical: preserves every type explicitly, for example { "$numberInt": "42" } and { "$date": { "$numberLong": "1577836800000" } }. Round-trips without loss.
• Relaxed: more readable, using plain JSON numbers and ISO-8601 dates ({ "$date": "2020-01-01T00:00:00Z" }), while keeping wrappers for types JSON can't represent (like Decimal128).
• Plain: strips all type wrappers to ordinary JSON. Convenient but lossy, an ObjectId becomes a plain string, a Decimal becomes a number.

When you'll use it

You get Canonical EJSON from mongoexport --jsonFormat=canonical and from many driver outputs. Convert to Relaxed for readable logs or docs, or to Plain to feed a tool that expects vanilla JSON.

Frequently asked questions