Requirements for Mercer | Mettl Mettl I/O

Requirements for Mercer | Mettl Mettl I/O

Mercer | Mettl I/O supports multiple IDEs and development tools out of the box. Some of these tools work only on specific browsers and/or browser modes.

The officially supported browsers for running Mercer | Mettl I/O based assessments are:
  1. Google Chrome
  2. Microsoft Edge
Please make sure not to use “Incognito” or “Private” modes in the web-browsers as they will result in error scenarios.


Cookies (including 3rd party cookies) are required to be enabled in the web-browser to properly run I/O based assessments.

Please follow the steps below to make sure that 3rd party cookies are enabled in your web browser:
  1. Open Google Chrome / Microsoft Edge.
  2. Click on the three dots in the upper right-hand corner of the browser window.
  3. Scroll down and click "Settings".
  4. Select the “Privacy and Security” section on the left.
  5. Click on "Third-Party Cookies". The following options will appear:
    1. Allow third-party cookies.
    2. Block third-party cookies in incognito.
    3. Block third-party cookies.
  6. Click on “Allow third-party cookies”, if not already selected.
  7. Close the browser using close button on top right corner and relaunch it.

Firewall Settings

Mercer | Mettl I/O spawns temporary development environments which are hosted on the “” domain.
Apart from the firewall requirements mentioned here, you need to allow access from your network to *