MailUp provides all the tools you need to let a visitor to your Web site or blog subscribe to a specific list using a subscription form. Such forms can be hosted by MailUp or placed directly on your Web pages.
See the following articles for technical details on how to perform GET/POST request to the MailUp API that allow you to subscribe, update, and unsubscribe recipients.
A subscription form on your website can transfer the inserted data to your MailUp account through simple calls to aspx pages. There are aspx pages that allow to insert, modify, search, and remove contacts in your MailUp distribution list. You can:
Subscribe a recipient to different lists and groups, using the “Codes table” as a reference (path: Settings > Codes table)
MailUp contains a handy drag-&-drop form builder that allows you to easily and quickly create responsive layout subscription forms. You can either have MailUp host the forms, or copy and paste the code onto your Web site.
Once the form has been submitted, the messages page will be displayed. This page is fully customizable in your MailUp account at Settings > List settings > Landing pages
As an alternative, you can specify a different URL on your website that your customers will be redirected to in different cases (subscription completed, duplicate email address, and so on).
MailUp uses Confirmed Opt-in by default (also called double opt-in). Once the form has been filled out, an email will be sent asking the new recipient to confirm her subscription by clicking into a link. The content and the sender of this email can be customized under Settings > List settings > Notifications > Confirmation request.
Users who confirm their subscription then receive a Welcome email, which can be personalized as well under Settings > List settings > Notifications > Welcome
You can subscribe someone to more than a list at the same time, while sending just one subscription confirmation request.
Using your forms
Of course, you can adapt existing forms so that they correctly communicate with MailUp. See more technical details on how to do so.
You can also leverage the REST or SOAP APIs to accomplish the same tasks (e.g. subscribing new recipients).
What's a "campo"?
The field code uses the word "CAMPO" because MailUp's original source code was developed in Italy. "Campo" means "Field" in Italian