Why Email Debugging for WordPress Matters
Sending real test emails is risky and slow. With a hosted mock SMTP, every wp_mail() message is captured instead of delivered. You can verify templates and headers instantly without spamming customers.
Quick Start
- Create an inbox at mockmail.io.
- In that inbox, copy your SMTP settings (host, port, username, password, encryption) from the dashboard.
- In WordPress, go to Plugins and search and install the WP Mail SMTP plugin.
Configure WP Mail SMTP
- Go to Plugins → Installed Plugins.
- Click on Activate below WP Mail SMTP
- Now you are shown the Setup Wizard. In the step Choose your Mailer, select Other SMTP.
- Fill in the fields using the values shown in your Mockmail inbox:
| Field | Value |
|---|---|
| SMTP Host | Use the host shown in Mockmail |
| Encryption | Set to None or SSL or TLS |
| SMTP Port | 25 |
| Authentication | On |
| SMTP Username | From your Mockmail inbox |
| SMTP Password | From your Mockmail inbox |
| From Email | e.g., noreply@yoursite.test (non-production) |
| From Name | e.g., YourSite (Test) |
- Finish the remaining steps of the wizard by accepting the pre-selected defaults and you may skip the license key input - the free version works just fine for debugging purposes.
Send a Test Email
Open the plugins page from your WP Admin center. Find the WP Mail SMTP plugin we previously installed and select tools and then Email Test. In mockmail.io, open your inbox and the email should automatically appear, if everything is configured correctly.
To test “real” flows, place a WooCommerce test order, submit a Contact Form 7 form, or trigger a password reset. All emails sent by your WordPress installation will always be delivered to your mockmail inbox, regardless of the original recipient address, and will never be sent to real customers.
Inspect & Share
For each captured email you can do the following within your Mockmail inbox:
- HTML: verify layout, images, and links
- Text: check the plain-text fallback
- Headers: confirm From/To/Reply-To and custom headers
- Attachments: download and review files
- Share: copy the shareable link to show your team/stakeholders
Note: Because messages aren’t sent through a live SMTP provider, SPF/DKIM/DMARC signing/validation doesn’t apply here. Use Mockmail to validate content and headers you control; handle deliverability setup later with your real SMTP provider.
Troubleshooting
- Email not appearing? Double-check host/port/encryption/credentials match your Mockmail inbox settings.
- Using containers? If WordPress runs in Docker while Mockmail is hosted, use the host from Mockmail, not
localhost. - Plugin bypassing SMTP? Some plugins call
mail()directly. Ensure they usewp_mail()or provide SMTP options. - From address wrong? Set it explicitly in WP Mail SMTP → Settings to avoid defaults like
wordpress@hostname.
Next step: When templates look good in Mockmail, switch WP Mail SMTP to your production SMTP provider and handle SPF/DKIM/DMARC there.