Using Email Analytics with Constant Contact
Email Analytics will work on Constant Contact if you are using a custom template. It looks like Constant Contact does not allow editing of their default templates, so if you are using this you will not be able to use the Email Analytics code. Email Analytics codes can only be used if you are using a custom template/advanced editor within the Custom code option.
Make sure to select the HTML option.
By selecting the Advanced Editor on the lower left-hand side of the page, you will then be able to paste in your own code.
Create a new tracking code in the Analytics tab of your Litmus account. Be sure to include Constant Contact's merge tag from step 2 of the setup process. It can be located within the drop-down list of popular ESPs. Copy and paste the tracking code from Litmus here. We recommend placing the tracking code by the closing </body> tag of your email, or as close to the bottom of your template as possible.
This article from Constant Contact's Knowledge Base is helpful for getting started with custom coded templates.