Mailster SendGrid Integration

Mailster SendGrid Integration connects SendGrid to the Mailster Newsletter Plugin for WordPress so you can send campaigns through SendGrid instead of your web host’s mail server.

Use it when SendGrid is your email delivery provider and you want to keep Mailster’s campaign editor, lists, and subscriber management.

This plugin requires Mailster 4.0 or newer and a SendGrid account with an API key. When SendGrid is the active delivery method, outgoing email content and delivery metadata are sent to SendGrid at api.sendgrid.com.

Why send Mailster newsletters with SendGrid?

• SendGrid delivery for Mailster — Registers SendGrid as a delivery method under Newsletter → Settings → Delivery.
• Web API or SMTP — Send with the SendGrid Mail Send API v3 (recommended), or relay through smtp.sendgrid.net using the username apikey. Secure SMTP uses port 465; otherwise the plugin uses port 587.
• API key check — Verifies the key against the SendGrid scopes endpoint and shows whether it is accepted.
• Categories — On the Web API, attach up to 10 SendGrid categories so you can group sends in SendGrid.
• Reply-to, attachments, and inline images — The Web API sends reply-to, file attachments, and inline images with the message.
• Campaign metadata — The Web API includes Mailster campaign, subscriber, and message IDs as SendGrid custom arguments, and forwards Mailster headers.
• Bounce and suppression sync — Reads SendGrid bounces, blocks, spam reports, and unsubscribes and applies them in Mailster.

How it works

1. Install and activate Mailster SendGrid Integration alongside Mailster 4.0+.
2. Create a SendGrid API key with Mail Send access and Suppressions read access, and authenticate the sender or domain in SendGrid.
3. Open Newsletter → Settings → Delivery, select the SendGrid tab, paste the API key, and save.
4. Choose WEB API or SMTP API. For SMTP, turn on the secure connection if you need port 465.
5. Send a test email from a verified From address, then run your Mailster campaigns through SendGrid.

Setup walkthrough: Send your newsletters via SendGrid.