Title: Flex SMTP
Author: Flex Plugins
Published: <strong>2026년 8월 25일</strong>
Last modified: 2026년 9월 16일

---

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![](https://ps.w.org/flex-smtp/assets/banner-772x250.png?rev=3677421)

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

# Flex SMTP

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

[다운로드](https://downloads.wordpress.org/plugin/flex-smtp.1.0.3.zip)

 * [세부사항](https://ko.wordpress.org/plugins/flex-smtp/#description)
 * [평가](https://ko.wordpress.org/plugins/flex-smtp/#reviews)
 *  [설치](https://ko.wordpress.org/plugins/flex-smtp/#installation)
 * [개발](https://ko.wordpress.org/plugins/flex-smtp/#developers)

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

## 설명

**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.

## 설치

 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**.

## FAQ

### 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.

## 후기

이 플러그인에 대한 평가가 없습니다.

## 기여자 & 개발자

“Flex SMTP”(은)는 오픈 소스 소프트웨어입니다. 다음의 사람들이 이 플러그인에 기여하였습니다.

기여자

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

[자국어로 “Flex SMTP”(을)를 번역하세요.](https://translate.wordpress.org/projects/wp-plugins/flex-smtp)

### 개발에 관심이 있으십니까?

[코드 탐색하기](https://plugins.trac.wordpress.org/browser/flex-smtp/)는, [SVN 저장소](https://plugins.svn.wordpress.org/flex-smtp/)
를 확인하시거나, [개발 기록](https://plugins.trac.wordpress.org/log/flex-smtp/)을
[RSS](https://plugins.trac.wordpress.org/log/flex-smtp/?limit=100&mode=stop_on_copy&format=rss)
로 구독하세요.

## 변경이력

#### 1.0.3

 * About FLEX lists the full suite, including Flex Clone and FLEX SMM & SEO.

#### 1.0.2

 * Tested up to WordPress 7.1.
 * About FLEX uses current suite names, including Flex SEO and SMM, Flex Website
   Security, and Flex Maintenance.

#### 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.

## 기초

 *  버전 **1.0.3**
 *  최근 업데이트: **2일 전**
 *  활성화된 설치 **10보다 적음**
 *  워드프레스 버전 ** 6.2 또는 그 이상 **
 *  다음까지 시험됨: **7.1.1**
 *  PHP 버전 ** 7.4 또는 그 이상 **
 *  언어
 * [English (US)](https://wordpress.org/plugins/flex-smtp/)
 * 태그:
 * [email](https://ko.wordpress.org/plugins/tags/email/)[mail](https://ko.wordpress.org/plugins/tags/mail/)
   [phpmailer](https://ko.wordpress.org/plugins/tags/phpmailer/)[smtp](https://ko.wordpress.org/plugins/tags/smtp/)
   [wp-mail](https://ko.wordpress.org/plugins/tags/wp-mail/)
 *  [고급 보기](https://ko.wordpress.org/plugins/flex-smtp/advanced/)

## 평점

아직 제출된 리뷰가 없습니다.

[Your review](https://wordpress.org/support/plugin/flex-smtp/reviews/#new-post)

[모든  리뷰 보기](https://wordpress.org/support/plugin/flex-smtp/reviews/)

## 기여자

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

## 지원

할 말 있으신가요? 도움이 필요하신가요?

 [지원 포럼 보기](https://wordpress.org/support/plugin/flex-smtp/)

## 기부

이 플러그인이 발전하도록 도우시겠습니까?

 [ 이 플러그인에 기부하기 ](https://flexible.am/)