Takayuki Miyoshi

<p>Double Opt-In Helper is a WordPress plugin that helps developers implement the double opt-in process in their plugins.</p>
<h4>What is double opt-in?</h4>
<p>Double opt-in is a procedure used to confirm user’s consent. Today, service providers are required to obtain clear consent from users prior to collecting or using their personal data. In some situations, however, asking the user to tick an “I agree.” checkbox is not sufficient. Double opt-in serves a useful role in such situations.</p>
<p>A typical double opt-in process starts by the service provider sending an email message to the user. The message includes a URL link to the provider’s website and asks the user to click the link if they agree on conditions. Usually, the URL includes some sort of unique random code that works as a token to confirm the user’s consent.</p>
<p>By doing this, the service provider can confirm that the real user (not a bot or someone else) has consented, because only the user should be able to access messages to their email address.</p>
<h4>I’m a developer. How can I use this plugin?</h4>
<p>First, register an “agent” who can handle double opt-in sessions for you, and knows what to do when a user opts-in.</p>
<p>To register an agent, use the <code>doihelper_register_agent()</code> function. <code>doihelper_register_agent()</code> takes two parameters: the name of the agent (required), and an optional associative array of arguments. The available arguments are:</p>
<ul>
<li><code>acceptance_period</code> — The length of time (in seconds) for how long a double opt-in session remains live. Default value: 86400 (24 hours)</li>
<li><code>optin_callback</code> — The callback function that will be called when a user opts-in.</li>
<li><code>email_callback</code> — The callback function that will be called to send a confirmation email.</li>
</ul>
<p>After registering an agent, start a double opt-in session by calling the <code>doihelper_start_session()</code> function. <code>doihelper_start_session()</code> takes two parameters: the name of the agent (required), and an optional associative array of arguments. The available arguments are:</p>
<ul>
<li><code>email_to</code> — The recipient’s email address, used for the confirmation email. If you omit this argument, no email will be sent. If you do not provide this argument, you will need to provide the user with the confirmation link another way.</li>
<li><code>properties</code> — The properties array of the session. This array is to be passed to the <code>optin_callback</code> function as its only parameter. While you can include any information into this, the primary purpose of it is to pass user-related data to the opt-in callback.</li>
</ul>
<p>The session data will be stored in the database until the user opts-in, or the acceptance period (from <code>doihelper_register_agent()</code>) expires.</p>


Double Opt-In Helper

Double Opt-In Helper is a WordPress plugin that helps developers implement the double opt-in process in their plugins.

Designed for Distinction

<p>MailPoet Opt-in for Formidable Forms is a simple, WordPress-native connector that adds subscribers to MailPoet when a Formidable form is submitted.</p>
<ul>
<li>Works with <strong>Formidable Forms (Free or Paid)</strong>.</li>
<li>Requires the <strong>MailPoet</strong> plugin to be installed and active.</li>
<li>Does <strong>not</strong> require Formidable’s MailPoet add-on.</li>
<li>Does <strong>not</strong> use third-party services.</li>
</ul>
<p>This plugin is intentionally scoped to opt-in subscriptions. It respects MailPoet subscription rules and does not force re-subscription of previously unsubscribed addresses.</p>
<h3>Features</h3>
<ul>
<li>Form <span aria-hidden="true" class="wp-exclude-emoji">→</span> MailPoet list connections (“rules”)</li>
<li>Explicit opt-in checkbox support</li>
<li>Optional “Always subscribe” mode per rule (use when your form has no opt-in field)</li>
<li>One list per rule</li>
<li>Compatible with MailPoet double opt-in workflows</li>
<li>Admin-only AJAX field mapping</li>
<li>Clean uninstall (removes plugin settings)</li>
</ul>
<h3>Requirements</h3>
<ul>
<li>Formidable Forms (free or paid)</li>
<li>MailPoet plugin (active)</li>
</ul>


Designed for Distinction – MailPoet Opt-in for Formidable Forms

A lightweight connector that subscribes Formidable Forms users to MailPoet lists using explicit consent.

Double Opt-In Helper vs Designed for Distinction – MailPoet Opt-in for Formidable Forms