Three plugins do the WordPress SMTP-relay job competently. Each has a distinct philosophy and a distinct failure mode, and the right choice depends less on a feature checklist than on what kind of operator is installing it. This piece names the three by use case, then explains why the recommendation lands where it does.
The verdict
For most operators installing their first WordPress mailer plugin: WP Mail SMTP. The setup wizard is the most polished in the category, 15 mailer integrations ship in the free version, and the four-million-install base means edge-case bugs find their way to the issue tracker faster than anywhere else. The Pro tier ($99/year on renewal, $49 first year, single site) adds logging and routing; the free version handles the core SMTP job.
For operators who want logging and routing in the free version, or who do not want their admin area pushing upgrades: FluentSMTP. Built by WPManageNinja as an open-source alternative to the freemium pattern, FluentSMTP includes email logging, resend, a fallback connection, and Amazon SES support without a paid tier. FluentSMTP includes a connection wizard, though its setup is more terse than WP Mail SMTP’s guided flow.
For operators who care about being told when delivery fails, on the channel they actually watch: Post SMTP. Its own mobile app, a Chrome extension, Slack, Pushover, and webhook alerts all ship in the free version. Logging, Gmail OAuth, and a resend-from-log button are free too. WP Mail SMTP documents browser-based push alerts that can be enabled on mobile devices; FluentSMTP documents Slack, Discord, Telegram, and Pushover alert integrations.
Each recommendation has a case where it is wrong, named in the relevant section below. Three newer plugins with large install bases (GoSMTP, SureMail, and Elementor’s Email Deliverability, formerly Site Mailer) are assessed under “Three newer plugins.” The four lesser plugins worth knowing about (Easy WP SMTP, SMTP Mailer, Gmail SMTP, YaySMTP) sit lower for the reasons listed under “Honourable mentions.”
How we read the field
This is a documentation-and-source comparison. The claims about each plugin’s free vs paid feature split, mailer support, install counts, and pricing are taken from each plugin’s wordpress.org page, the vendor’s own pricing page, and the readme.txt in the plugin source. Where a claim depends on hands-on UX evaluation (setup-wizard quality, error-message clarity, the polish of the admin interface), it is stated as such.
Install counts and pricing referenced here are current as of 2026-11-02. Plugin versions are current as of 2026-11-05: WP Mail SMTP 4.10.3, FluentSMTP 2.4.5, Post SMTP 4.0.2. WP Mail SMTP’s published prices include a $50 first-year discount; renewal prices are cited throughout this piece as the steady-state cost.
For the no-plugin path (using wp_mail() filters directly), see WordPress SMTP without a plugin; that guide is one slice of the broader WordPress without the plugin hub, the minority path for sites that would rather not run an SMTP plugin at all. For the broader setup that places the chosen plugin alongside DNS records, verification, and troubleshooting, see How to set up email on WordPress.
WP Mail SMTP
WP Mail SMTP, by Awesome Motive (the WPForms / OptinMonster / MonsterInsights group), is the category’s incumbent: 4 million-plus active installations and a setup wizard that gets non-technical users through the configuration the first time. Post SMTP has a three-step setup wizard too; WP Mail SMTP also offers a setup wizard for first-time configuration.
The 15 free mailers cover the providers most WordPress operators reach for: SendLayer, SMTP.com, Brevo, Gmail and Google Workspace (via OAuth), Elastic Email, Mailgun, Mailjet, SendGrid, Postmark, SparkPost, SMTP2GO, Resend, Mandrill, MailerSend, plus a generic “Other SMTP” option. Three integrations are gated behind Pro: Microsoft 365 / Outlook, Amazon SES, and Zoho Mail. If the operator’s chosen relay is one of those three, the Pro tier ($99/year on renewal) becomes a hard requirement, not an optional add.
The free version also covers a From-name and From-email override, which forces a single sender identity across every email WordPress sends regardless of the originating plugin. This is one of those small features that prevents a recurring deliverability problem (plugin authors hardcoding their own From addresses, breaking DMARC alignment) and is the kind of thing operators only realise they wanted after the first time it bites them.
What sits behind Pro. The Pro tier (single site, $99/year on renewal) adds email logging, weekly email reports, backup connections (automatic fallback to a second mailer if the primary fails), smart routing (conditional logic to send different emails through different mailers), rate limiting, multisite settings, and failure alerts via Slack / Teams / Discord / SMS / webhook. The three Pro-only mailers (M365, SES, Zoho) sit here too. Resend-from-log lives in the Pro tier, since the log itself is Pro-only. The wordpress.org readme marks the background send queue, Optimized Email Sending, as Pro too, but version 4.10.3 of the free plugin includes it and never checks for the Pro tier.
Higher tiers: Elite ($149/year on renewal) adds White Glove Setup. Developer ($249/year on renewal) covers 20 sites. Agency ($449/year on renewal) covers 100 sites. Every tier has a $50 first-year discount; the renewal is the long-term price.
| Tier | Sites | First year | Renewal |
|---|---|---|---|
| Pro | 1 | $49 | $99/yr |
| Elite | 1 | $99 | $149/yr |
| Developer | 20 | $199 | $249/yr |
| Agency | 100 | $399 | $449/yr |
The single feature most operators reach for after the initial mailer configuration is email logging. WP Mail SMTP gates it behind Pro. This is the line that ends a lot of “should I stay free?” conversations: for operators who need to know whether a specific email actually left WordPress, the choice is paying for WP Mail SMTP Pro or installing FluentSMTP or Post SMTP, both of which log in their free tiers. The plugin you regret a year in is usually the one that did not log. That decision happens at install time.
Where WP Mail SMTP is the wrong choice. Agencies running 20+ client sites on the Developer tier ($249/year on renewal) are not getting a different plugin than what the Pro tier offers; they are paying for the site count. If the agency’s relay is something other than Microsoft 365, Amazon SES, or Zoho, the free FluentSMTP plugin covers the same functional ground without the per-site licence. Operators who object on principle to admin-area upgrade prompts are not going to enjoy WP Mail SMTP; the upsell messaging is persistent, by Awesome Motive’s house style, and not configurable away.
The plugin’s reach and the wizard make it nanoPost’s default for first-time installs and for client estates where the operator who configures the plugin is not the operator who will troubleshoot it six months later. For everyone else, the next two contenders are worth considering before defaulting.
FluentSMTP
FluentSMTP, by WPManageNinja, is the open-source answer to the freemium pattern. 700,000-plus active installations, version 2.4.5, and a published philosophy that the plugin should be free and feature-complete rather than a funnel into a paid tier. There is no FluentSMTP Pro; the vendor’s commercial work sits in adjacent products (Fluent Forms, FluentCRM), and the SMTP plugin is the free anchor. The result is the plugin most aligned with what an operator coming from outside the WordPress commercial-plugin culture expects: install, configure, done, no upgrade prompts in the dashboard.
The free version includes multiple SMTP connections (run two relays at once and route specific From addresses through each), one fallback connection (if a send fails, the plugin tries that connection instead), email logging with resend, and API-based integrations for the providers that offer one. Coverage includes Amazon SES (which WP Mail SMTP gates behind Pro), Mailgun, SendGrid, Brevo, Postmark, SparkPost, SMTP2GO, Elastic Email, Netcore, Cloudflare Email Sending, toSend, and the generic SMTP option, plus Zoho Mail over SMTP. Mailjet is not on the list; FluentSMTP reaches it over generic SMTP. Gmail and Microsoft 365 via OAuth are also covered in the free plugin.
The connection-routing feature is the closest thing this category has to a unique capability. An operator running a WooCommerce store can route transactional order confirmations through Postmark (where deliverability is the priority) while routing marketing newsletters through SendGrid (where price-per-message at volume is the priority), and the routing logic lives inside FluentSMTP. WP Mail SMTP offers “Smart Routing” in Pro for the same purpose; FluentSMTP includes it free.
Where FluentSMTP is the wrong choice. FluentSMTP includes a connection wizard, though its setup is more terse than WP Mail SMTP’s guided flow. An operator who has never configured SMTP credentials and does not understand the difference between port 587 STARTTLS and port 465 SSL will get further faster with WP Mail SMTP’s guided flow. FluentSMTP assumes a reader who can pair a relay’s docs with the plugin’s connection form without intermediation. Most professional WordPress operators clear that bar; first-time users may not.
The plugin’s documentation, while serviceable, is thinner than WP Mail SMTP’s. Mailer-specific quirks (SES sandbox-mode behaviour, M365 SMTP AUTH timeline, Postmark’s broadcast vs transactional split) are not addressed in FluentSMTP’s docs the way they are in WP Mail SMTP’s knowledge base. For these, the operator is reading the relay’s own documentation, which is usually where the answer lives anyway.
The plugin is nanoPost’s recommendation for operators who want logging, resend, and routing without a per-site licence, and who object to admin-area upgrade pressure as a matter of taste.
Post SMTP
Post SMTP, by WPExperts, has the longest lineage of the three. It started life as Postman SMTP, was rebranded and taken over by its current maintainers, and has been actively developed since. 300,000-plus active installations, version 4.0.2, and a feature posture that emphasises one capability the other two do not match.
That capability is failure notification. When an email fails, the free Post SMTP 4.0.2 can alert the admin email address, Slack, Pushover, any webhook, a Chrome extension, or Post SMTP’s own iOS and Android app, which also shows the email log. For an operator running a WooCommerce store, this is the difference between hearing about a broken order-confirmation email at 2 PM via the user complaint and hearing about it at 8 AM on a phone while it is still recoverable. FluentSMTP also sends free failure alerts, to Slack, Discord, Telegram, or Pushover, and has no first-party app of its own. WP Mail SMTP puts its alerts in Pro. Microsoft Teams (Business plan) and Twilio SMS alerts are Post SMTP Pro additions.
The free version also includes OAuth 2.0 for Gmail (Microsoft 365 OAuth is in Pro, as it is at WP Mail SMTP), built-in email logging with a resend button, a configuration wizard that auto-detects common SMTP settings from the entered hostname, custom Reply-To / Cc / Bcc configuration, and a fallback SMTP service for when the primary fails. FluentSMTP and WP Mail SMTP Pro both log and resend; Post SMTP’s distinguishing addition is the mobile app, free.
What sits behind Pro. Post SMTP restructured its commercial offering in the last two years; what was previously a constellation of per-extension purchases ($30-100 per extension) is now Post SMTP Pro, a single subscription. The Pro tier adds the M365, Amazon SES, and Zoho Mail premium SMTP integrations (the same three that WP Mail SMTP also gates), advanced logging, email open-tracking, and additional alert channels (Microsoft Teams, Twilio SMS). Pricing varies by site count and is published on the 
Post SMTP pricing page.
Where Post SMTP is the wrong choice. The admin interface, while functional, is the least polished of the three. The plugin shows its age in places where WP Mail SMTP and FluentSMTP have had design refreshes Post SMTP has not. Operators who prioritise interface polish over feature coverage will notice. The mobile app for delivery alerts is a real feature but the experience is closer to a utility than a product; the operator who is going to actually look at the app is the operator who already wanted the alerts.
The changelog is more visibly that of a small team than of the larger plugins’ release cadences. Recent versions have included fixes for socket-related errors and PHP-version compatibility issues that most operators will never see, but the fix-and-react pattern is closer to the surface than in WP Mail SMTP or FluentSMTP.
Post SMTP is nanoPost’s recommendation specifically for operators who run WooCommerce, membership, or LMS sites where A transactional email is the automated message a WordPress site sends in response to a single user action – a password reset, an order confirmation, a form receipt – addressed to the user who triggered it. Read full reference → delivery is operational rather than incidental: sites where being told about a failure in real time has commercial consequences. For sites where the operator will only ever check email logging if a user complains, the failure-notification advantage is not earning its keep.
Three newer plugins
These three each have an install base on a par with or above the honourable mentions. None displaces the three picks, for the reasons given against each.
GoSMTP (by Softaculous; 500,000-plus installs, version 1.2.5) splits free and paid the way WP Mail SMTP does, with less on the free side. The free version connects SMTP.com, Brevo, Mailgun, SendGrid, SparkPost, SendLayer, Postmark, Maileroo, and generic SMTP. Gmail and Google Workspace, Outlook / Office 365, Amazon SES, Zoho, Elastic Email, SMTP2GO, Resend, and MailerSend are Pro, and so are email logging, resend, failure notifications (email, Slack, Discord), and smart routing. Its own credits say its mailer API connectors are derived from FluentSMTP. An operator who wants logging free, or Gmail without paying, gets both from FluentSMTP.
SureMail (by Brainstorm Force, the company behind the Astra theme; 200,000-plus installs, version 2.0.3, on wordpress.org since January 2025) is free, with no paid tier listed. Like FluentSMTP, it has email logging with resend and multiple connections with fallback, though a backup only covers mail with the same From address as the connection it protects. Where FluentSMTP has one fallback connection for the whole site, SureMail can chain several. It adds one automatic retry of a failed send, 30 minutes later, which FluentSMTP does not have. Failure notifications to Slack, Discord, Telegram and others need Brainstorm Force’s separate OttoKit product, formerly SureTriggers. Its mailers include Amazon SES, SendGrid, Mailgun, Mailjet, Gmail / Google Workspace, MailerSend, Postmark, SparkPost, Elastic Email, Brevo, SMTP2GO, Netcore, Zoho Mail, Emailit, and Brainstorm Force’s own SureContact, plus generic SMTP. Mailjet, MailerSend and Zoho Mail are native here, where FluentSMTP reaches them over generic SMTP. The 2.0.3 code marks SureMail’s Microsoft 365 connection as not yet available. FluentSMTP has a track record four years longer and connects Microsoft 365 today, so it stays the free pick. SureMail is the better fit for a site that does not need Microsoft 365 and wants failed mail retried automatically, more than one backup connection, or a native Zoho Mail, Mailjet or MailerSend connection.
Email Deliverability by Elementor (formerly Site Mailer; 200,000-plus installs, version 1.4.7) is not an SMTP plugin. It sends every wp_mail() message through Elementor’s own email service, so there is no relay to choose and no credentials to enter, and it needs a connected Elementor account. It keeps a 30-day email log with resend and a suppression list, and it supports a custom sending domain. The free trial covers 200 emails; Elementor’s paid plans are sized by monthly volume (1,000 emails a month for one site, 10,000 a month across three). The comparison above does not apply to it, because the plugin and the relay are one product. Because the plugin routes every wp_mail() message through Elementor’s service, moving to another email service requires switching or reconfiguring the site’s email-sending path.
Honourable mentions
These four plugins are installed on enough WordPress sites to warrant mention. None is the recommendation for an operator still choosing; each works for the operators who chose it.
Easy WP SMTP (now maintained by the WP Mail SMTP team under Awesome Motive; 500,000-plus installs) overlaps almost entirely with WP Mail SMTP’s free tier and is under the same parent. The two plugins exist because of acquisition history; the practical implication is that an operator already using SendLayer (the SMTP service the same group operates) will find slightly tighter integration in Easy WP SMTP than in WP Mail SMTP, but for any other relay, WP Mail SMTP is a more complete free plugin.
SMTP Mailer (by naa986; 70,000-plus installs) is a deliberately minimal plugin: SMTP credentials, From override, test send. No logging, no failure alerts, no Pro tier. For an operator who wants exactly that and nothing else, it works. For an operator who will want logging two weeks later, it is the wrong starting point.
Gmail SMTP (by naa986, same author; 10,000-plus installs) is SMTP Mailer scoped specifically to Gmail with the OAuth flow built in. It predates WP Mail SMTP’s native Gmail OAuth integration and has not added a reason to choose it over the larger plugins since.
YaySMTP (10,000-plus installs) is a newer entrant with a clean interface and SMTP-and-API support, including a native SendPulse mailer that WP Mail SMTP and FluentSMTP lack. For the established providers, the larger plugins have more mature support.
Choosing for your situation
You are configuring SMTP on a single WordPress site for the first time. Use WP Mail SMTP. The setup wizard is the reason. The free tier covers your relay unless your relay is M365, SES, or Zoho. If it is one of those three, install FluentSMTP or pay for WP Mail SMTP Pro.
You manage WordPress for clients and want a free plugin that does not push upgrades in the dashboard. Use FluentSMTP. The interface stays out of the way, logging and routing are free, and the operator who inherits the site after you leave will not get nagged into a paid plan they do not need.
You run a WooCommerce store, membership site, or LMS where email delivery has commercial consequences. Use Post SMTP and configure the failure notifications. Logging is necessary; being told in real time when delivery fails is necessary.
You want email to work without opening an account with a relay. Elementor’s Email Deliverability bundles the relay with the plugin. Check the monthly volume against its plans before relying on it.
You are choosing an SMTP relay and have not yet picked a plugin. The relay decision matters more than the plugin decision. See the SMTP services directory before locking the plugin in.
What we did not test
This piece is a documentation and source comparison. The following are real questions that a hands-on test would answer, and that this piece does not:
- Side-by-side comparison of the error UI when each plugin is given deliberately broken credentials. The plugin that surfaces “auth failed at smtp.host.com because port 587 is blocked” is a meaningfully different product from the one that surfaces “Mailer failed to start.”
- The actual feel of Post SMTP’s failure-notification flow under real-world conditions: does Chrome push survive an extended browser-closed window, does Slack post arrive within minutes of the failure, does the alert clear when the next send succeeds.
- Behaviour on OAuth token refresh failures, DNS resolution timeouts, and TLS-handshake errors. These are the failure modes most operators actually encounter; the documentation rarely covers what the plugin does with them.
- Pro-only features without a trial. WP Mail SMTP Pro’s smart routing, Post SMTP Pro’s open tracking: not covered here from hands-on use.
- Multi-site network installs. WordPress multisite changes the surface for each plugin and is its own piece.
- Plugin behaviour under WP-CLI, headless, or REST-API contexts where the admin interface is not the surface. Some failures are admin-only.
The recommendation here stands on documented features and the existing nanoPost individual reviews.
Corrections
- 2026-11-05: an earlier version said FluentSMTP has fallback servers and that the next connection tries after a failure, which implied a chain. FluentSMTP has one fallback connection for the whole site.
- 2026-11-05: an earlier version said flatly that neither WP Mail SMTP nor FluentSMTP has an app of its own. WP Mail SMTP’s documentation shows browser-based push alerts on mobile devices.
- 2026-11-05: an earlier version said SureMail has the FluentSMTP feature set and listed automatic retry among those features. FluentSMTP has no automatic retry; SureMail makes one retry.
- 2026-11-05: an earlier version listed background queue processing among WP Mail SMTP’s Pro features; version 4.10.3 of the free plugin ships the queue and never checks for a paid tier.
- 2026-11-05: an earlier version pointed Maileroo and MailerSend users to YaySMTP, which has no mailer for either, and left Zoho Mail off SureMail’s mailer list.
- 2026-10-19: an earlier version implied Post SMTP’s free OAuth covers Microsoft 365; Post SMTP 4.0.2 puts the Microsoft 365 connection in its paid Pro extension.
- 2026-10-19: an earlier version said Post SMTP was the only plugin whose free version sends failure alerts, listed Twilio SMS as free and webhook alerts as Pro; in Post SMTP 4.0.2 Twilio SMS is Pro and webhook alerts are free, and FluentSMTP also sends free alerts to Slack, Discord, Telegram, and Pushover. The Post SMTP pick stands on its free mobile app.
- 2026-10-23: an earlier version listed Mailjet among FluentSMTP’s built-in mailers; FluentSMTP 2.4.1 has no Mailjet mailer and reaches Mailjet over generic SMTP.
- 2026-11-02: an earlier version said WP Mail SMTP was the only one of the three with a setup wizard; Post SMTP has a three-step setup wizard too.