New to Constant Contact? An Overview of Our Email Marketing Core

For developers who are just getting started integrating with Constant Contact, we wanted to provide some context for understanding our email marketing product platform. We think of our platform in three major buckets: contacts, content, and analytics. Here are a few things for you to consider when integrating with Constant Contact through our API.


Constant Contact allows marketers to bundle multiple email addresses into a list, then send individual emails to each recipient. Marketers frequently use third-party tools to generate that list, such as lead-generation, invoice, and ecommerce tools (or whatever your application might be). They use filters or queries within these tools to slice and dice data appropriately to feed a list in Constant Contact. Developers can create a seamless integration between their tools and Constant Contact so that marketers can extract the most information out of their tools when implementing a campaign.

With Constant Contact, marketers can build a highly relevant message and create interactive conversations with specific groups of recipients – relevance is what makes the difference between impactful marketing and spam (and, of course, we use some techniques so that these emails are not confused with spam). Further, marketers can scale those groups as the positive response grows, without having to break recipient lists into subgroups to manage volume.

Let’s say a marketer wanted to send an email only to the subscribers who spent more than $100 with her company last month. That information might be contained in an ecommerce application, such as Big Commerce. The parsing and development of those lists normally happens in the ecommerce platform. Our open API lets customers synchronize and segment lists based on data from outside sources. We’re integrated natively with hundreds of applications that serve small businesses, and that number keeps growing. That includes content management systems (CMS); business management apps; customer relationship management (CRM) systems, such as Salesforce, Microsoft Dynamics, SugarCRM, and Zoho; and business intelligence/analytics platforms.

Developers should plan for the following when setting up lists to be exported into Constant Contact:

  • What data should be included or excluded to reach the right recipients?
  • Do you want the marketer to use a list already contained in the ecommerce platform?
  • Do you want to create a brand new list or overwrite an existing list?
  • There is a 20,000-contact limit per bulk upload in Constant Contact. If your list is larger than this, you will need to break it up into chunks of 20,000.
  • After a bulk upload, lists won’t appear immediately. Depending on the number of variables and recipients in the list, it may take from one to five minutes for the system to process it.


Constant Contact is incredible easy to use so that customers can be up and running in just five minutes. They use our wizard environment and choose from hundreds of email templates, or create a template, upload a logo or image, type in a message—and send.

However, Constant Contact is not a “black box” that forces users to consolidate all their activity in our system. Our API supports developers in creating HTML emails from scratch on their own platforms, without the need to use our interface. This is especially helpful in the case of automated emails around anniversaries or special events that would typically be triggered on an ecommerce or CRM system and layered into a business’s overall marketing campaign.

We encourage developers to link their content-related platforms to our API. Content can be compiled anywhere, but customers can still use Constant Contact as their platform to send it to their lists, which gives them the added benefit of targeted delivery, reporting, and analytics. For example, Xydo, a content curation service, integrates with Constant Contact so that a marketer who finds a relevant article in XYDO can send that article with a custom message through the Constant Content API to her mailing list.


You can’t talk about marketing without talking about analytics. It’s one thing to send a bulk email. It’s much more valuable to find out:

  • Who opened it and when?
  • What did they click on?
  • Which addresses bounced, and why?
  • Who unsubscribed?

Constant Contact tracks all of this information and makes it available through our API. Combining the data from both systems ultimately provides a richer information model for contacts. That means marketers can answer more nuanced questions, such as:

  • How many email messages did that person receive before purchasing on my site?
  • Which messages did they open and which messages triggered the most sales?
  • Did our sales increase during the time period of our special offer to everyone who spent more than $100 per month?


With the Constant Contact API, developers can help marketers build a richer model of their customer base and expand that base effectively through highly targeted, informed email campaigns that deliver highly specific analytics on campaign performance. We support open standards that allow you to take advantage of Constant Contact’s functionality and rich email templates without locking customer data inside a “black box” or building a custom integration that only works once.

Welcome to Constant Contact. Please feel free to explore and ask us anything—we’re here to help. We look forward to seeing your integrations with our API and having our customers become your customers, too.

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