Install

brew tap mongodb/brew
brew install mongodb-community

(You can also install a specific version, e.g. mongodb-community@8.0, depending on what is available.)

Start MongoDB service

brew services start mongodb/brew/mongodb-community

Stop service later

brew services stop mongodb/brew/mongodb-community

Check service status

brew services list

3) What is mongod?

mongod is the MongoDB server process (daemon). It is the actual database engine that:

• Listens for incoming connections
• Reads/writes data files
• Handles indexes, queries, and replication
• Manages storage engine behavior (WiredTiger by default)

Think of mongod as: "the database itself running in the background."

Example (manual start):

mongod --dbpath /usr/local/var/mongodb

When started through Homebrew services, this process runs automatically in the background.

4) What is mongo?

mongo is the legacy command-line shell client used to connect to a running MongoDB server.

You can think of it as:

• mongod = server
• mongo = client shell that talks to server

In newer MongoDB releases, the modern shell is mongosh, which replaces mongo in many setups.

Example connection:

mongosh

or

mongosh "mongodb://localhost:27017"

5) How they work together

A simple mental model:

1. Start the server (mongod)
2. Connect with shell/client (mongo or mongosh)
3. Run database commands (create DB, collections, queries, inserts)

If mongod is not running, your client cannot connect.

6) Quick first-run checklist

• Install MongoDB (website or Homebrew)
• Confirm mongod --version
• Start MongoDB server/service
• Connect using mongosh
• Run a test command:

show dbs

Final note

For modern development, prefer mongosh over the old mongo shell, but conceptually the server-client split is the same: mongod runs the database, and the client tool connects to it.