onetwothreesend

One Two Three Send is a complete newsletter workflow inside WordPress. The plugin uses the Claude API (you supply the key) to draft issues from your site’s content, gives you inline AI editor tools to polish the copy, runs a pre-send audit to catch common mistakes, and sends through Resend or SMTP to subscribers stored in your own database.
<h4>What’s included</h4>
<ul>
<li>AI newsletter generator — Claude drafts a newsletter from your recent posts, site tagline, and a manual description you provide. Tone selector (Friendly / Professional / Casual / Authoritative) and length selector (~200, ~400, ~700 words).</li>
<li>AI editor — select any paragraph and click Rewrite, Shorten, Expand, or Fix grammar. Generate 5 alternative subject lines in one click. Tone check, local spam-word scan.</li>
<li>Pre-send audit — one click runs 10 checks: subject length, body word count, unsubscribe reference, link count, link format, spam triggers, placeholder leaks, readability (Flesch-Kincaid), read time, structural sanity. Each check returns pass / warn / fail with a plain-language explanation.</li>
<li>Scheduling — manual, daily, weekly, fortnightly, monthly. Manual-approval mode emails the admin before any send. Auto-send is opt-in.</li>
<li>Email delivery — Resend (API) or SMTP (any provider).</li>
<li>Subscribers — local database with filtering, CSV export, one-click token-based unsubscribe.</li>
<li>Signup forms — inline form via shortcode <code>[otts_form id="1"]</code>, Gutenberg block, or PHP <code>onetwothreesend_render_form(1)</code>.</li>
<li>Welcome email — automatic, configurable subject and body with <code>{first_name}</code>, <code>{email}</code>, <code>{site_name}</code>, <code>{from_name}</code> placeholders.</li>
<li>Lead magnet delivery — upload a PDF, zip, or any allowed file. New subscribers receive a signed, time-limited download link in the welcome email. Expired links auto-refresh when clicked, no manual resending.</li>
</ul>
<h4>External services</h4>
This plugin calls the following external APIs using credentials you provide. No data is sent to any third party without you entering a key first.
<ul>
<li>Anthropic Claude API (<code>api.anthropic.com</code>) — for drafting and editing newsletters. You provide the API key in Settings → AI. Terms: https://www.anthropic.com/legal/consumer-terms. Privacy: https://www.anthropic.com/legal/privacy.</li>
<li>Resend (<code>api.resend.com</code>) — optional, for email delivery. You provide the API key in Settings → Email Provider if you choose Resend. Terms: https://resend.com/legal/terms-of-service. Privacy: https://resend.com/legal/privacy-policy.</li>
</ul>
The plugin itself does not phone home. It does not contact onetwothreesend.com or any server other than the ones you explicitly configure above.
<h4>Companion plugin</h4>
A companion plugin (One Two Three Send Pro, distributed separately) can extend this with Stripe paywalls, Mailchimp / MailerLite / Brevo / ConvertKit providers, popup and slide-in forms, and more. One Two Three Send is fully functional on its own — the companion plugin is optional. <a href="https://onetwothreesend.com/pricing/" rel="nofollow ugc">Pricing and details</a>.
<h4>Useful links</h4>
<ul>
<li><a href="https://onetwothreesend.com/features/" rel="nofollow ugc">Features overview</a> — full feature breakdown with screenshots.</li>
<li><a href="https://onetwothreesend.com/docs/" rel="nofollow ugc">Documentation</a> — setup walkthroughs and troubleshooting guides.</li>
<li><a href="https://onetwothreesend.com/pricing/" rel="nofollow ugc">Pricing</a> — free tier, monthly, annual, and founder plans for the companion newsletter and pro plugin.</li>
<li><a href="https://onetwothreesend.com/privacy/" rel="nofollow ugc">Privacy policy</a>.</li>
<li><a href="https://onetwothreesend.com/contact/" rel="nofollow ugc">Contact / support</a> — for questions the FAQ below doesn’t answer.</li>
</ul>

One Two Three Send

AI newsletters for WordPress. Draft with Claude, audit before sending, deliver via Resend or SMTP, manage subscribers — all from your admin.

sendmachine

Sendmachine’s official plugin will enable you to:
Set up signup forms 
You can set up a signup form in a few easy steps: connect using the provided API <a href="https://www.sendmachine.com/admin/#/myaccount/smtp_settings" rel="nofollow ugc">credentials</a>, select a contact list where your visitors will subscribe and you’re basically good to go. The signup form is available as a widget (in your widget area) or as a shortlink by pasting <code>[sm_subscribe_form]</code> in a post or page.
Add subscribe checkboxes 
Allow users to subscribe to your contact list only by checking a checkbox in certain website areas like comment form or register form.
Sync your wordpress users with a specific contact list 
You want to send emails to all your users but don’t know how? Well, don’t worry, we can help you with that. After you’ve successfully selected a contact list, you can use the “Sync users” button, to subscribe all your users to that contact list.
Send emails through our services 
No need for nasty, geeky configurations. Just set a from email, an optional from name and you are good to go. Also, make sure that “enable email sending” is set to <code>on</code>. 
If you set a from email that doesn’t already exist in your sendmachine account as a sender address, a confirmation email will be generated and sent to that address. 
Not quite sure if you’ve done everything right? You can test if everything is ok by sending a test email. If you got the mail, you can sit back and relax: you’ve done it, otherwise something went wrong.
Send transactional emails 
No more “dog ate my email” excuses. Using our services you can now monitor an email’s activity (opens, clicks, geolocations, user agents). In order to enable this option, after you install our plugin, go to “email settings” tab and check that “Register” and/or “Comment” checkboxes. Basically, if you tick that checkboxes on each email sent, that coresponds with that action, we add a custom tracking header: <code>X-Sendmachine-Campaign: campaign_name</code>, where campaign_name is the name of the transactional campaign that will be created, or updated if already exists. Campaign’s name can be found/modified next to every action’s checkbox.
Send news feed 
You can send a newsletter directly from the admin panel with the latest posts. You can choose to build your newsletter with the latest 5, 10, 15 or 20 posts, set newsletter’s width, color and content.
<h3>External Services</h3>
This plugin connects to the following Sendmachine services:
1. Sendmachine REST API
Used for list, campaign management and statistics. Specifically:
<ul>
<li>Authenticates your account using your API credentials (username and password).</li>
<li>Retrieves your contact lists, sender addresses, and SMTP connection settings.</li>
<li>Subscribes visitors to your chosen contact list, including their email address and any additional form fields they complete.</li>
<li>Creates, and sends email campaigns containing your latest blog posts.</li>
<li>Retrieves your account’s email credit usage for the dashboard.</li>
</ul>
This service is contacted whenever you perform any of the above actions from the WordPress admin or from a front-end subscribe form.
2. Sendmachine SMTP
When the email sending service is enabled and configured, all outgoing emails from your WordPress site are routed through Sendmachine’s SMTP servers. This includes core WordPress emails such as password resets, new user registrations, and comment notifications, as well as any emails sent by other plugins or themes.
<ul>
<li>Service: <a href="https://www.sendmachine.com" rel="nofollow ugc">https://www.sendmachine.com</a></li>
<li>Privacy Policy: <a href="https://www.sendmachine.com/confidentialitate.html" rel="nofollow ugc">https://www.sendmachine.com/confidentialitate.html</a></li>
<li>Terms of Service: <a href="https://www.sendmachine.com/termeni-si-conditii.html" rel="nofollow ugc">https://www.sendmachine.com/termeni-si-conditii.html</a></li>
</ul>

Sendmachine for WordPress

Official Sendmachine plugin featuring subscribe forms, users sync, news feed, email sending and transactional campaigns.

One Two Three Send vs Sendmachine for WordPress