What is FluentSMTP plugin?
FluentSMTP is a completely free, open-source WordPress SMTP plugin developed by WPManageNinja — the team behind Fluent Forms and FluentCRM. Its defining characteristic is that every feature is free permanently: email logging, multiple simultaneous mailer connections, native API integrations with major email services, and automatic routing. There is no paid version, no premium tier, and no feature gating.
FluentSMTP supports native API connections to Amazon SES, SendGrid, Mailgun, Postmark, Brevo (Sendinblue), SparkPost, and Google Workspace, plus generic SMTP as a fallback. Its multi-connection feature allows adding multiple email service providers and routing emails automatically — for example, routing FluentCRM bulk campaigns through Amazon SES while routing WooCommerce transactional emails through Postmark for superior inbox placement. This routing capability is equivalent to WP Mail SMTP Pro’s multiple mailer feature, available at zero cost.
The plugin’s email log captures every email WordPress sends, with full message content, status (sent/failed), and diagnostic error information. For sites using FluentCRM, Fluent Forms, and Fluent Support, FluentSMTP is the natural email delivery layer that ties the ecosystem together. For all other WordPress sites, it is the most feature-complete free SMTP plugin available — the only meaningful trade-off compared to WP Mail SMTP Pro is the absence of dedicated professional support and Microsoft 365 one-click OAuth.
Need Help With FluentSMTP Setup, Troubleshooting, or Customization?
Need help with FluentSMTP? Whether you are dealing with errors, broken functionality, styling problems, plugin conflicts, or advanced customization, we can help you fix the issue and get the plugin working properly on your WordPress site.
Get FluentSMTP Expert HelpKey Features
- Completely free — no paid version or feature gating
- Native API connections: Amazon SES, SendGrid, Mailgun, Postmark, Brevo, SparkPost, Google Workspace
- Generic SMTP fallback
- Multiple simultaneous mailer connections
- Automatic email routing between mailers
Pros & Cons
Pros
- 100% free — all features including email logging and multiple connections at no cost
- Multiple mailer connections and routing available free (equivalent to WP Mail SMTP Pro feature)
- Native API integrations provide faster, more reliable delivery than generic SMTP
Cons
- Community-based support only — no dedicated professional support for email delivery emergencies
- No Microsoft 365 one-click OAuth setup (available in WP Mail SMTP Pro)
Free vs Premium
100% free. No paid version. All features included at no cost forever.
Common Problems & Fixes
FluentSMTP email log is growing very large and slowing down the database — how do I manage the log size?
FluentSMTP stores complete email records including message content in the WordPress database. For sites sending high volumes (bulk FluentCRM campaigns, WooCommerce order emails), this log can reach gigabytes. Go to FluentSMTP → Settings → Email Logs and configure automatic log cleanup — set the retention period (e.g., delete logs older than 30 days) and enable scheduled cleanup. For immediate size reduction, use the “Bulk Delete” option to remove old log entries. Also consider whether all WordPress email types need to be logged — disable logging for specific senders if full log retention is unnecessary.
FluentSMTP is connected but test emails are failing with an authentication error — how do I resolve this?
Authentication errors indicate the API key or credentials are incorrect or have been revoked. Go to FluentSMTP → Settings → Connections and re-enter the API key for your sending service. For Amazon SES, ensure the IAM user credentials have the ses:SendEmail and ses:SendRawEmail permissions. For SendGrid, verify the API key has “Mail Send” permissions. For Gmail/Google Workspace, re-authorize the OAuth connection if it has expired. After updating credentials, run the test email tool to confirm the new credentials work.
Some WordPress emails are bypassing FluentSMTP and sending via PHP mail() — how do I ensure all emails route through FluentSMTP?
FluentSMTP hooks into WordPress’s wp_mail() function — any plugin that uses wp_mail() will use FluentSMTP automatically. Emails bypassing SMTP are using PHPMailer or direct PHP mail() calls outside the WordPress hook system. This is uncommon but can occur with legacy or poorly coded plugins. Identify the bypassing plugin by reviewing server mail logs. Contact the plugin developer and request they use wp_mail() for email sending, which is the WordPress standard.
Customization & Developer Notes
How do I configure FluentSMTP to use Amazon SES as the primary mailer with SendGrid as a fallback?
In FluentSMTP → Settings → Connections, add both Amazon SES and SendGrid as separate connections. Go to Connection Management and set Amazon SES as the primary connection. Configure the fallback to SendGrid — FluentSMTP will automatically attempt the primary mailer and fall back to the secondary if the primary fails. This dual-mailer setup provides resilience against single-provider outages with zero additional plugin cost.
Can FluentSMTP send different email types through different mailers without manual routing configuration?
FluentSMTP supports smart routing based on From Email address. Configure routing rules in Settings → Email Routing: route emails from your WooCommerce “From” address to a high-deliverability transactional mailer (Postmark or Amazon SES), and route bulk marketing emails from FluentCRM to a higher-volume, lower-cost mailer (Mailgun or Amazon SES standard). Transactional emails benefit from providers optimized for one-to-one delivery; bulk campaigns benefit from providers optimized for bulk deliverability.
Frequently Asked Questions
Is FluentSMTP reliable for a WooCommerce store sending thousands of order emails per month?
FluentSMTP is reliable — its deliverability is determined by the SMTP service it connects to, not by the plugin itself. For a WooCommerce store with high order volume, pair FluentSMTP with Amazon SES (excellent deliverability, $0.10 per 1,000 emails) or Postmark (premium transactional deliverability, free for 100 emails/month, then $1.25 per 1,000). The plugin handles the connection; the SMTP provider handles deliverability infrastructure.
Does FluentSMTP work well with FluentCRM for bulk email campaigns?
Yes — FluentSMTP and FluentCRM are designed to work together as a self-hosted email marketing stack. FluentCRM handles contact management, campaign creation, and automation; FluentSMTP handles email delivery via your preferred SMTP provider. The combination is the most cost-effective full-featured self-hosted email marketing solution for WordPress. Use Amazon SES with FluentSMTP for bulk campaign delivery — the cost-per-email is significantly lower than any email marketing SaaS at equivalent volume.
Can FluentSMTP break after updates?
Yes, that can happen, especially on older sites with many plugins. This usually happens when the plugin, theme, and add-ons are updated out of sequence. In most cases, testing on staging catches the issue before it reaches the live site. From experience, backups and changelog reviews save a lot of cleanup time.
What should I check before installing FluentSMTP?
Start by checking whether another plugin already does the same job. In most cases, overlap is what creates avoidable conflicts and performance issues. A common issue is installing a plugin because it looks convenient without checking the stack first. From experience, a short compatibility review avoids most of the pain later.