Title: Flex SMTP
Author: Flex Plugins
Published: <strong>2026 年 8 月 25 日</strong>
Last modified: 2026 年 8 月 25 日

---

搜索插件

![](https://ps.w.org/flex-smtp/assets/banner-772x250.png?rev=3665345)

![](https://ps.w.org/flex-smtp/assets/icon-256x256.png?rev=3665345)

# Flex SMTP

 作者：[Flex Plugins](https://profiles.wordpress.org/flexfields/)

[下载](https://downloads.wordpress.org/plugin/flex-smtp.1.0.1.zip)

 * [详情](https://cn.wordpress.org/plugins/flex-smtp/#description)
 * [评价](https://cn.wordpress.org/plugins/flex-smtp/#reviews)
 *  [安装](https://cn.wordpress.org/plugins/flex-smtp/#installation)
 * [开发进展](https://cn.wordpress.org/plugins/flex-smtp/#developers)

 [支持](https://wordpress.org/support/plugin/flex-smtp/)

## 描述

**Flex SMTP** is the mail layer for the FLEX plugin suite. Flex Forms (and anything
else that calls `wp_mail()`) can leave SMTP credentials out of form settings. This
plugin owns delivery: provider presets, SMTP or HTTP API, a test send, and a searchable
log.

It is built for sites that already use FLEX plugins, and for hosts that block outbound
SMTP ports 465/587. HTTP API sending uses WordPress `wp_remote_post` only — no vendor
SDKs are bundled.

 * Provider presets (Gmail, Microsoft 365, SendGrid, Mailgun, Amazon SES, and more)
 * SMTP for every provider, or HTTP API for transactional services
 * From email / name, default From replacement, and optional Force From
 * One-click test email
 * Searchable delivery log with retention
 * Copies old Flex Forms SMTP options on first activate

Enable is off by default. Mail stays on the WordPress default mailer until you save
a provider and turn Enable on.

CSS and JavaScript are loaded from this plugin only. There is no telemetry and no
remote update checker.

#### Privacy

SMTP usernames, passwords, and API keys are stored in your WordPress database (leave
a secret field blank when saving to keep the stored value). The optional email log
stores recipient, subject, success/fail, and error text. Only administrators can
view the log or settings.

When Enable is on, message content is sent to the SMTP host or HTTP API you configured.
Flex SMTP does not send mail to any other remote service. See **External services**.

### External services

This plugin connects to a third-party mail service only after an administrator chooses
that provider, saves credentials, and turns **Enable** on (or clicks Send test).
Until then, WordPress uses the default mailer. The plugin does not phone home.

**What data is sent (every provider):** From, To, Cc, Bcc, Reply-To, subject, body,
and attachments from `wp_mail()`. SMTP also sends the saved username and password.
HTTP API also sends the saved API key, and the secret, domain, or region when that
provider requires them.

**When data is sent:** On each `wp_mail()` call while Enable is on, and when an 
administrator sends a test email.

**Why:** To deliver WordPress mail (password resets, form notifications, WooCommerce,
and so on) through the account you already have with that provider.

#### Amazon SES

Amazon Simple Email Service delivers mail when **Amazon SES** is selected. SMTP 
connects to `email-smtp.{region}.amazonaws.com` (for example `email-smtp.us-east-
1.amazonaws.com`). HTTP API posts SendRawEmail to `email.{region}.amazonaws.com`.
The region is the one you pick in settings.

Service: [Amazon SES](https://aws.amazon.com/ses/)
 [Terms of Service](https://aws.amazon.com/service-terms/)
[Privacy Policy](https://aws.amazon.com/privacy/)

#### Gmail / Google Workspace

Sends mail through Google SMTP (`smtp.gmail.com`) when that provider is selected.
Uses an app password (OAuth is not included).

Service: [Gmail](https://mail.google.com/)
 [Terms of Service](https://policies.google.com/terms)
[Privacy Policy](https://policies.google.com/privacy)

#### Microsoft 365 / Outlook

Sends mail through Microsoft SMTP (`smtp.office365.com`) when that provider is selected.
Uses SMTP AUTH and, when required, an app password.

Service: [Microsoft 365](https://www.microsoft.com/microsoft-365)
 [Terms of Service](https://www.microsoft.com/servicesagreement)
[Privacy Policy](https://privacy.microsoft.com/privacystatement)

#### Yahoo Mail

Sends mail through Yahoo SMTP (`smtp.mail.yahoo.com`) when that provider is selected.
Uses an app password.

Service: [Yahoo Mail](https://mail.yahoo.com/)
 [Terms of Service](https://legal.yahoo.com/us/en/yahoo/terms/otos/index.html)
[Privacy Policy](https://legal.yahoo.com/us/en/yahoo/privacy/index.html)

#### Zoho Mail

Sends mail through Zoho SMTP (`smtp.zoho.com`) when that provider is selected.

Service: [Zoho Mail](https://www.zoho.com/mail/)
 [Terms of Service](https://www.zoho.com/terms.html)
[Privacy Policy](https://www.zoho.com/privacy.html)

#### iCloud Mail

Sends mail through iCloud SMTP (`smtp.mail.me.com`) when that provider is selected.
Uses an app-specific password.

Service: [iCloud](https://www.icloud.com/)
 [Terms of Service](https://www.apple.com/legal/internet-services/icloud/)
[Privacy Policy](https://www.apple.com/legal/privacy/)

#### SendGrid

Sends mail through SendGrid SMTP (`smtp.sendgrid.net`) or the SendGrid HTTP API 
when that provider is selected.

Service: [SendGrid](https://sendgrid.com/)
 [Terms of Service](https://www.twilio.com/en-us/legal/tos)
[Privacy Policy](https://www.twilio.com/en-us/legal/privacy)

#### Mailgun

Sends mail through Mailgun SMTP (`smtp.mailgun.org` or `smtp.eu.mailgun.org`) or
the Mailgun HTTP API (`api.mailgun.net` or `api.eu.mailgun.net`) when that provider
is selected. HTTP API also sends the Mailgun sending domain you enter.

Service: [Mailgun](https://www.mailgun.com/)
 [Terms of Service](https://www.mailgun.com/legal/terms/)
[Privacy Policy](https://www.mailgun.com/legal/privacy-policy/)

#### Postmark

Sends mail through Postmark SMTP (`smtp.postmarkapp.com`) or the Postmark HTTP API
when that provider is selected. The API key is the Postmark server token.

Service: [Postmark](https://postmarkapp.com/)
 [Terms of Service](https://postmarkapp.com/terms-of-service)
[Privacy Policy](https://www.activecampaign.com/legal/privacy-policy)

#### Brevo

Sends mail through Brevo SMTP (`smtp-relay.brevo.com`) or the Brevo HTTP API when
that provider is selected.

Service: [Brevo](https://www.brevo.com/)
 [Terms of Service](https://www.brevo.com/legal/termsofuse/)
[Privacy Policy](https://www.brevo.com/legal/privacypolicy/)

#### Mailjet

Sends mail through Mailjet SMTP (`in-v3.mailjet.com`) or the Mailjet HTTP API when
that provider is selected. HTTP API also sends the Mailjet API secret.

Service: [Mailjet](https://www.mailjet.com/)
 [Terms of Service](https://www.mailjet.com/legal/terms/)
[Privacy Policy](https://www.mailjet.com/legal/privacy-policy/)

#### SparkPost

Sends mail through SparkPost SMTP (`smtp.sparkpostmail.com` or `smtp.eu.sparkpostmail.
com`) or the SparkPost HTTP API when that provider is selected. SparkPost is a Bird
service.

Service: [SparkPost](https://www.sparkpost.com/)
 [Terms of Service](https://bird.com/legal/terms)
[Privacy Policy](https://bird.com/legal/privacy)

#### SMTP2GO

Sends mail through SMTP2GO SMTP (`mail.smtp2go.com`) or the SMTP2GO HTTP API when
that provider is selected.

Service: [SMTP2GO](https://www.smtp2go.com/)
 [Terms of Service](https://www.smtp2go.com/terms/)
[Privacy Policy](https://www.smtp2go.com/privacy/)

#### Resend

Sends mail through Resend SMTP (`smtp.resend.com`) or the Resend HTTP API when that
provider is selected.

Service: [Resend](https://resend.com/)
 [Terms of Service](https://resend.com/legal/terms-of-service)
[Privacy Policy](https://resend.com/legal/privacy-policy)

#### Custom SMTP

Sends mail to the SMTP host you type in settings. That host’s own terms and privacy
policy apply. Flex SMTP does not choose or document a third party for Custom.

## 安装

 1. Upload the `flex-smtp` folder to `/wp-content/plugins/`, or install the zip via**
    Plugins  Add New  Upload Plugin**.
 2. Activate **Flex SMTP**.
 3. Open **Flex SMTP  Settings**, choose a provider, enter credentials, set From email,
    enable routing, and save.
 4. Send a test email, then confirm the result under **Email Log**.

## 常见问题

### Does this replace the SMTP settings that used to live in Flex Forms?

Yes. Flex Forms now calls `wp_mail()` only. Activate Flex SMTP once to copy the 
old Forms SMTP options, then manage delivery here.

### Does Gmail or Microsoft 365 use OAuth?

No. Those providers use SMTP with an app password (and SMTP AUTH enabled on Microsoft
365). OAuth is not included.

### What is the difference between SMTP and HTTP API?

SMTP talks to the provider’s mail server through PHPMailer. HTTP API posts the message
with `wp_remote_post` and skips PHPMailer. Use HTTP API if outbound ports 465/587
are blocked. Gmail, Microsoft 365, Yahoo, Zoho, iCloud, and Custom are SMTP only.

### Will mail still go through my web host?

Not while Enable is on. Messages go to your SMTP host or the provider API. Turn 
Enable off to return to the default WordPress mailer.

### What is stored in the email log?

Recipient, subject, success or fail, error text, and time. It does not store API
keys or passwords. Disable Email log if you do not want delivery history.

### What happens when I uninstall?

Deleting the plugin removes settings, credentials, and the log table. Deactivating
alone keeps your data.

## 评价

此插件暂无评价。

## 贡献者及开发者

「Flex SMTP」是开源软件。 以下人员对此插件做出了贡献。

贡献者

 *   [ Flex Plugins ](https://profiles.wordpress.org/flexfields/)
 *   [ Flex Dev ](https://profiles.wordpress.org/hovoqoch/)

[帮助将「Flex SMTP」翻译成简体中文。](https://translate.wordpress.org/projects/wp-plugins/flex-smtp)

### 对开发感兴趣吗?

您可以[浏览代码](https://plugins.trac.wordpress.org/browser/flex-smtp/)，查看[SVN仓库](https://plugins.svn.wordpress.org/flex-smtp/)，
或通过[RSS](https://plugins.trac.wordpress.org/log/flex-smtp/?limit=100&mode=stop_on_copy&format=rss)
订阅[开发日志](https://plugins.trac.wordpress.org/log/flex-smtp/)。

## 更新日志

#### 1.0.1

 * Expand External services: each provider lists what is sent, when, why, and working
   terms/privacy URLs.
 * Replace 404 Zoho and Mailjet legal links. SparkPost now points to current Bird
   legal pages.

#### 1.0.0

 * Initial release: SMTP and HTTP API providers, test email, delivery log, and Flex
   Forms migration.

## 额外信息

 *  版本 **1.0.1**
 *  最后更新：**2 天前**
 *  活跃安装数量 **不到10**
 *  WordPress 版本 ** 6.2 或更高版本 **
 *  已测试的最高版本为 **7.1**
 *  PHP 版本 ** 7.4 或更高版本 **
 *  语言
 * [English (US)](https://wordpress.org/plugins/flex-smtp/)
 * 标签
 * [email](https://cn.wordpress.org/plugins/tags/email/)[mail](https://cn.wordpress.org/plugins/tags/mail/)
   [phpmailer](https://cn.wordpress.org/plugins/tags/phpmailer/)[smtp](https://cn.wordpress.org/plugins/tags/smtp/)
   [wp-mail](https://cn.wordpress.org/plugins/tags/wp-mail/)
 *  [高级视图](https://cn.wordpress.org/plugins/flex-smtp/advanced/)

## 评级

尚未提交反馈。

[您的评价](https://wordpress.org/support/plugin/flex-smtp/reviews/#new-post)

[查看全部评论](https://wordpress.org/support/plugin/flex-smtp/reviews/)

## 贡献者

 *   [ Flex Plugins ](https://profiles.wordpress.org/flexfields/)
 *   [ Flex Dev ](https://profiles.wordpress.org/hovoqoch/)

## 支持

有话要说吗？是否需要帮助？

 [查看支持论坛](https://wordpress.org/support/plugin/flex-smtp/)

## 捐助

您愿意支持这个插件的发展吗?

 [ 捐助此插件 ](https://flexible.am/)