How to Export MongoDB Collection to JSON File

To export a MongoDB collection to a JSON file, use the mongoexport command-line tool with the --collection and --out options. For example, mongoexport --db yourDB --collection yourCollection --out output.json exports the collection data into a JSON file named output.json.

Syntax

The basic syntax for exporting a MongoDB collection to a JSON file is:

• mongoexport: The command-line tool to export data.
• --db: Specifies the database name.
• --collection: Specifies the collection name to export.
• --out: Defines the output file path and name.
• --jsonArray (optional): Exports data as a JSON array instead of one JSON document per line.

bash

mongoexport --db <database_name> --collection <collection_name> --out <file_name>.json [--jsonArray]

Example

This example exports the users collection from the mydatabase database into a file named users.json. It uses the --jsonArray option to export the data as a JSON array.

bash

mongoexport --db mydatabase --collection users --out users.json --jsonArray

Output

[
  {"_id": {"$oid": "60c72b2f9af1f2d9c8e4b8a1"}, "name": "Alice", "age": 30},
  {"_id": {"$oid": "60c72b3a9af1f2d9c8e4b8a2"}, "name": "Bob", "age": 25}
]

Common Pitfalls

Common mistakes when exporting collections include:

• Not specifying the correct database or collection name, resulting in no data exported.
• Forgetting to use --jsonArray if you want a valid JSON array file; otherwise, the output is one JSON document per line.
• Running mongoexport without having it installed or not in your system's PATH.
• Not having proper permissions to read the database or write the output file.

bash

Wrong (missing --jsonArray):
mongoexport --db mydatabase --collection users --out users.json

Right (with --jsonArray):
mongoexport --db mydatabase --collection users --out users.json --jsonArray

Quick Reference

Option	Description
--db	Specify the database to export from
--collection	Specify the collection to export
--out .json	Output file path and name
--jsonArray	Export data as a JSON array (optional)
--query ''	Export documents matching a filter (optional)

Key Takeaways

Use the mongoexport tool with --db, --collection, and --out options to export collections.

Add --jsonArray to export data as a valid JSON array file.

Ensure correct database and collection names to avoid empty exports.

Check permissions and mongoexport installation before running the command.

You can filter exported data using the --query option if needed.