Description

API is an addon that enables integration endpoints to query, subscribe, update, and remove subscribers in Newsletter through controlled external calls. It is intended for developers and technical teams that need to connect forms, their own systems, member areas, or external applications to the email marketing flow already managed by the base plugin.

API Key Features

  • Subscriber endpoints
    Allows you to manage contact registrations from external systems.
  • Integration with Newsletter
    Connects external calls to the data maintained by the base plugin.
  • Subscription workflows
    Helps you register new subscribers without relying only on standard forms.
  • Contact updates
    Facilitates adjustments to subscriber data through custom routines.
  • Developer use
    Provides a technical layer for tailored integrations.

API Benefits

  • Tailored integrations
    Lets you connect Newsletter to internal systems and your own workflows.
  • Less manual work
    Reduces duplicate registrations by automating contact entry and updates.
  • More technical control
    Helps teams define when and how data will be synchronized.
  • Expansion of the ecosystem
    Expands Newsletter usage in projects with specific needs.

Who Is the API Intended For?

  • Developers who need to integrate Newsletter with external applications.
  • Agencies that create custom lead capture and management workflows.
  • WordPress projects with forms, restricted areas, or their own registration systems.

How to Download the API

The API is available for download on this page. To put it live, go to Plugins > Add New > Upload plugin in the WordPress admin panel, upload the addon file, and activate it. Then, keep Newsletter active so the integration works.

The API addon expands Newsletter for projects that need to go beyond native forms, allowing registrations and subscriber updates to be connected to your own systems. For lead capture operations, member areas, or internal automations, it creates a technical bridge between WordPress and external processes without changing the base plugin’s core logic.

Frequently asked questions

Is Newsletter API GPL-licensed?

Yes. Newsletter API is distributed under the GPL (GNU General Public License). You may legally use, modify and redistribute it on as many sites as you want.

Can I use Newsletter API on multiple sites?

Yes. You can install Newsletter API on as many sites as you want. Only automatic updates through Ultrapack Auto Updater have a limit: from 3 to 80 sites, depending on the plan.

How much does Newsletter API cost at Ultrapack?

Newsletter API costs US$2.99 as a single purchase, and it is also included in the subscription plans starting at US$12/mo (VIP I).

Does Newsletter API include updates?

Yes. The current version of Newsletter API is 2.5.8, published at Ultrapack on Aug 30, 2026. Subscribers update straight from the WordPress dashboard with UAU (Ultrapack Auto Updater).

Is Newsletter API scanned before publication?

Yes. Every version of Newsletter API goes through a malware scan (ClamAV and YARA rules, at UltraHub) before it is published.

What are the requirements for the plugin Newsletter API?

Requires WordPress 6.1 or higher and PHP 7.4 or higher. Tested up to WordPress 7.1.