Connect to a Cluster

Atlas provides instructions via the Connect Dialog for connecting to an Atlas cluster from the following sources:

Atlas provides instructions for connecting to an Atlas cluster using the following MongoDB command line tools in the Command Line Tools tab:

Binary Import and Export Tools
Data Import and Export Tools
Set Up Diagnostics

See Connect to a Cluster using Command Line Tools for complete documentation.

Connection Limits and Instance Sizes

Atlas sets the limits for concurrent incoming connections based on instance size:

Instance Size Maximum Number of Concurrent Incoming Connections
M0 100
M2 100
M5 100
M10 350
M20 700
M30 2000
M40 / M40 Low CPU * 4000
M50 / M50 Low CPU * 16000
M60 / M60 Low CPU * 32000
M80 Low CPU * 64000
M90 64000
M100 96000
M140 96000
M200 / M200 Low CPU * 128000
M300 128000
M400 Low CPU * 128000

* Low CPU instances are available with AWS clusters only.


Atlas reserves a small portion of connections to each Atlas cluster for supporting Atlas services. Contact Atlas support for more information on Atlas reserved connections.


To access a cluster, you must connect from an IP address on the Atlas project’s IP whitelist. If you need to add an IP address to the whitelist, you can do so in the Connect dialog. You can also add the IP address from the Security tab.

Use the Connect dialog to Connect to Your Cluster


Open the Connect dialog.

Go to the Clusters view. Click the Connect button for the cluster to which you wish to connect.


From the Connect dialog, review the IP Whitelist.

Atlas only allows client connections to the cluster from entries in the project’s whitelist.

Atlas displays any entries already on the project whitelist in the Connect modal under Check the IP Whitelist. If you do not see the IP address of your client on the list, you can:

  • Click Add Entry to add a single IP address or a CIDR-notated range of addresses.

    For Atlas clusters deployed on Amazon Web Services and using VPC Peering, you can add a Security Group associated with the peer VPC.

  • Click Add Current IP Address to add your current IP address.

  • Click Allow Access From Anywhere to allow access from any IP address.


    Using Allow Access From Anywhere results in all clusters in the Atlas project being publically accessible. Consider the security risks of having public-facing MongoDB clusters before using this option.


Select your preferred connection method.

For Choose a connection method, Atlas provides instructions for each listed connection method. Click your preferred connection method and follow the instructions given.

For connecting via a command line tool such as mongodump or mongorestore, use the Command Line Tools tab for an auto-generated template for connecting to your Atlas cluster with your preferred tool.