Title: Custom SMTP: Email Deliverability – FREE & Easy-to-use
Author: Nicolas Verlhiac
Published: 11. 4. 2024
Last modified: 31. 7. 2026
---
Prohledat pluginy
# Custom SMTP: Email Deliverability – FREE & Easy-to-use
Autor: [Nicolas Verlhiac](https://profiles.wordpress.org/nicolasverlhiac/)
[Stáhnout](https://downloads.wordpress.org/plugin/custom-smtp.2.7.3.zip)
[Aktuální náhled](https://cs.wordpress.org/plugins/custom-smtp/?preview=1)
* [Podrobnosti](https://cs.wordpress.org/plugins/custom-smtp/#description)
* [Hodnocení](https://cs.wordpress.org/plugins/custom-smtp/#reviews)
* [Instalace](https://cs.wordpress.org/plugins/custom-smtp/#installation)
* [Vývojáři](https://cs.wordpress.org/plugins/custom-smtp/#developers)
[Podpora](https://wordpress.org/support/plugin/custom-smtp/)
## Popis
### Make your WordPress email arrive
WordPress still hands your email to the PHP mail() function. Most hosts have switched
it off or throttled it because spammers loved it, and where it still runs, unauthenticated
mail lands in spam. If your contact form says thank you and nothing ever arrives,
this is why.
Custom SMTP sends your email through the provider you already use instead: your
host’s SMTP server, Gmail, Outlook, Brevo, SendGrid, Mailgun, Postmark or the Amazon
SES API. It logs every message with its outcome, lets you preview and resend failures,
and alerts you when sending spikes or starts failing. Everything is in the free
plugin: no account to create, no third-party relay, no pro version.
Built for modern WordPress: **WordPress 7.0 ready**, **PHPMailer 7.0.2 compatible**,**
stateless / cloud-ready** (Docker, Kubernetes), and **fully translated in English
and French**.
Documentation lives at [customsmtp.com/docs/](https://customsmtp.com/docs/), with
[step-by-step guides](https://customsmtp.com/guides/) for twelve providers and a
[developer guide](https://customsmtp.com/developers/) covering constants, environment
variables and the Amazon SES API.
### Send through your own SMTP provider
Point the plugin at the server you already pay for or the free tier you already
use, with a preset that fills the technical values for you:
* **Presets for twelve providers**: Gmail, Outlook, Amazon SES, SendGrid, Mailgun,
Brevo, Postmark, Mailjet, Zoho, Yahoo, iCloud and Scaleway, plus „Other / Custom“
for any SMTP server.
* **From Name and From Email** applied to every outgoing email, with optional Reply-
To, CC and BCC.
* **SSL/TLS encryption**, and optional authentication for relay servers that need
none.
* **Password encrypted at rest** (AES-256-CBC with your WordPress salts), never
displayed back in the form.
* **Test without guessing**: test the SMTP connection without sending anything,
or send yourself a real test email.
### A log of every email, with preview and resend
Never wonder if your emails were sent again. Logging works out of the box and captures
every message going through wp_mail(): WooCommerce order notifications, contact
form submissions, password resets, all of it.
* Delivery status (sent or failed) with the exact SMTP error when a message fails,
and the stored headers for advanced troubleshooting.
* **Preview the email body in wp-admin**, in an Outlook-style sidebar, without
sending anything again; view the HTML source, or download any email as an HTML
file for archiving.
* **Resend a failed email** straight from the logs once your configuration is fixed.
* Search by recipient, subject or status; filter by date range; export to CSV for
reporting and compliance.
* Configurable retention with automatic purge (30 days by default), and content
storage you can switch off in one click.
### Unusual Usage Alerts
A compromised contact form or a runaway plugin can turn your site into a spam relay,
and a revoked password or an exhausted provider quota can stop your emails silently.
Custom SMTP watches for both and warns you.
* **Sending spikes** — get an email when more messages than expected go out within
an hour or a day. Thresholds are absolute, never relative, so a quiet site that
sends a handful of emails a week is never woken up by statistical noise.
* **Delivery failures** — get warned as soon as several emails fail in a row, or
when too many of the last messages sent failed. Counted over the last emails
sent rather than over a period of time, so it works just as well on a site that
sends twice a week as on a busy store.
* **A channel that survives the outage** — alerts go out by email, to an optional
HTTPS webhook (Slack, Teams, any JSON endpoint), and to a persistent notice in
wp-admin, because the one moment you need the alert is the moment email itself
is broken.
* **No noise** — a configurable cooldown keeps an ongoing incident from filling
your inbox, and the alert email is never logged nor counted against your own
thresholds.
* **Off by default** — turn it on in Settings and set the thresholds that match
your site.
### Manage WordPress Notifications
WordPress sends a handful of emails on its own, and some of them get old fast: a
notice to the administrator every single time a user resets their password, a report
after every automatic plugin update, a message for every comment awaiting moderation.
Switch off the ones you do not want, one checkbox each, no code.
* **Password reset and new user notices to the administrator** — the user still
gets their reset link and their welcome email, only the copy to the admin stops.
* **Automatic update reports** — core, plugins and themes, separately.
* **Comment notifications** — awaiting moderation, and new comment to the post
author.
* **Nothing is hidden from you** — a notification you switch off is never created,
so it will not appear in the Email Logs either, and the screen tells you that.
* **Account recovery is never at risk** — the emails users need to regain access
to their account are deliberately out of reach of this screen.
* **Off means off, on stays on** — installing or updating the plugin never silences
an email your site was already sending.
### Deliverability, privacy, security
* Cooperates with the automatic Envelope-From / Return-Path behavior introduced
in WordPress 6.9, which improves SPF, DKIM and DMARC alignment on strict hosts(
Amazon SES, Postmark, etc.).
* UTF-8 and emoji handled end-to-end in subjects, bodies and headers.
* All data stays in your WordPress database: no third-party calls, no telemetry,
and no external processor to declare in your GDPR records.
* Email preview rendered in a sandboxed iframe, so no JavaScript from a logged
email ever runs in wp-admin.
* All admin actions protected with nonces and capability checks; the SMTP password
is encrypted at rest.
### For developers: containers, config-as-code, Amazon SES API
The [developer guide](https://customsmtp.com/developers/) covers this surface in
depth; the short version:
* **Stateless and cloud-ready**: no filesystem writes, no shared storage, safe
on read-only filesystems. Works on Docker, Kubernetes, AWS ECS/Fargate, Google
Cloud Run, and with Bedrock or Trellis stacks.
* **Every setting from a constant or environment variable**: define `CUSTOM_SMTP_
` and it overrides the saved value everywhere, with the field shown
read-only in wp-admin and a badge naming the variable. On Multisite, a network-
wide option can configure every site at once.
* **Amazon SES API with IAM roles**: send through the SESv2 API authenticated by
your ECS task role or EC2 instance role, with no access keys and no stored credentials.
Raw MIME preserves HTML, attachments, CC/BCC, Reply-To and custom headers, and
it works with or without the AWS SDK for PHP. Details in the FAQ below.
* **Abilities API (WordPress 6.9+)**: `custom-smtp/connection-health` and `custom-
smtp/send-test-email` are exposed to MCP-enabled AI assistants and automation
tools (n8n, Make), behind the same `manage_options` capability check as wp-admin.
## Snímky obrazovky
[⌊Email Logs - every email is logged with its delivery status, and failed sends
show the exact SMTP error. Search, filter by status or date, and export to CSV.⌉⌊
Email Logs - every email is logged with its delivery status, and failed sends show
the exact SMTP error. Search, filter by status or date, and export to CSV.⌉[
Email Logs – every email is logged with its delivery status, and failed sends show
the exact SMTP error. Search, filter by status or date, and export to CSV.
[⌊SMTP Settings - pick a provider preset (Gmail, Brevo, SendGrid and more), fill
in your credentials and you are done. The status bar confirms email delivery is
active.⌉⌊SMTP Settings - pick a provider preset (Gmail, Brevo, SendGrid and more),
fill in your credentials and you are done. The status bar confirms email delivery
is active.⌉[
SMTP Settings – pick a provider preset (Gmail, Brevo, SendGrid and more), fill in
your credentials and you are done. The status bar confirms email delivery is active.
[⌊Email Preview - click any logged email to read its full content in an Outlook-
style sidebar, without sending anything again.⌉⌊Email Preview - click any logged
email to read its full content in an Outlook-style sidebar, without sending anything
again.⌉[
Email Preview – click any logged email to read its full content in an Outlook-style
sidebar, without sending anything again.
[⌊Unusual Usage Alerts - get warned by email, webhook or admin notice when sending
spikes or delivery failures pile up. Every threshold is yours to tune.⌉⌊Unusual
Usage Alerts - get warned by email, webhook or admin notice when sending spikes
or delivery failures pile up. Every threshold is yours to tune.⌉[
Unusual Usage Alerts – get warned by email, webhook or admin notice when sending
spikes or delivery failures pile up. Every threshold is yours to tune.
[⌊Test tools - check your configuration in one click: test the SMTP connection or
send yourself a real test email.⌉⌊Test tools - check your configuration in one click:
test the SMTP connection or send yourself a real test email.⌉[
Test tools – check your configuration in one click: test the SMTP connection or
send yourself a real test email.
## Instalace
1. Install Custom SMTP either via the WordPress.org plugin repository or by uploading
the files to your server.
2. Navigate to Settings > Custom SMTP in the WordPress admin.
3. Select a provider preset (Gmail, Outlook, AWS SES, SendGrid, Mailgun, Brevo, Postmark,
Mailjet, Zoho, Yahoo, iCloud, Scaleway) or pick „Other / Custom“ and enter your
SMTP details manually.
1, 2, 3: You’re done!
On AWS (ECS/Fargate, EC2)? Choose the **Amazon SES (API · IAM role)** mailer instead
of SMTP to send with no stored credentials — see the SES question in the FAQ.
## Nejčastější dotazy
### Where do I find the documentation?
On [customsmtp.com/docs/](https://customsmtp.com/docs/), which covers every screen
and setting of the plugin. Each provider preset also has its own [step-by-step guide](https://customsmtp.com/guides/),
with the exact values the preset fills in. The [developer guide](https://customsmtp.com/developers/)
goes further: forcing any setting from a PHP constant or an environment variable,
running on immutable or containerized WordPress, and sending through the Amazon
SES API with an IAM role.
For anything not covered there, the support forum on this page is the right place
to ask.
### What SMTP settings should I use?
Custom SMTP includes presets for popular providers (Gmail, Outlook, AWS SES, SendGrid,
etc.). Just select your provider and settings are auto-filled.
### List of SMTP Servers
Here’s a reference list of common SMTP servers:
**Professional Email Services**
* SendGrid: smtp.sendgrid.net – TLS – Port 587 *
Mailgun: smtp.mailgun.org – TLS – Port 587 * Amazon SES: email-smtp.[region].amazonaws.
com – TLS – Port 587 * Brevo (Sendinblue): smtp-relay.brevo.com – TLS – Port 587*
Postmark: smtp.postmarkapp.com – TLS – Port 587 * Mailjet: in-v3.mailjet.com – TLS–
Port 587 * Scaleway: smtp.tem.scaleway.com – TLS – Port 587
**Consumer Email Providers**
* Gmail: smtp.gmail.com – TLS – Port 587 * Outlook/
Office365: smtp.office365.com – TLS – Port 587 * Yahoo Mail: smtp.mail.yahoo.com–
TLS – Port 587 * iCloud: smtp.mail.me.com – TLS – Port 587 * Zoho: smtp.zoho.com–
TLS – Port 587 * AOL: smtp.aol.com – TLS – Port 587 * GMX: smtp.gmx.com – SSL –
Port 465
**ISP Email (Regional)**
* Comcast: smtp.comcast.net – Port 587 * Verizon: outgoing.
verizon.net – SSL – Port 465 * AT&T: smtp.mail.att.net – SSL – Port 465 * Orange:
smtp.orange.net – Port 25 * T-Online: securesmtp.t-online.de – TLS – Port 587 *
1&1 IONOS: smtp.1and1.com – TLS – Port 587
Note: Settings may vary. Contact your provider for exact configuration.
### Does it work with WooCommerce?
Yes! Custom SMTP logs all emails sent from WordPress, including WooCommerce order
confirmations, shipping notifications, and customer emails.
### Is it compatible with contact form plugins?
Yes, it works with Contact Form 7, WPForms, Gravity Forms, and any plugin that uses
WordPress wp_mail() function.
### Is it compatible with stateless/containerized WordPress?
Yes. Custom SMTP is fully stateless-compatible and works on ephemeral infrastructure(
Docker, Kubernetes, AWS ECS/Fargate, Google Cloud Run, etc.) without shared storage
like EFS or NFS.
The plugin stores all data in the WordPress database:
* Settings in `wp_options`
* Email logs in a custom database table
* CSV exports streamed directly to the browser (no temp files)
* Log purge scheduled via WP-Cron (database-backed)
It also works with modern WordPress stacks like Bedrock and Trellis, and can run
on a read-only filesystem.
**Notes for stateless deployments:**
* Ensure WordPress salts (`LOGGED_IN_KEY`, `LOGGED_IN_SALT`) are consistent across
all instances — the SMTP password encryption depends on them.
* If `DISABLE_WP_CRON` is set to `true`, configure an external cron to trigger `
wp-cron.php` so automatic log purge runs properly.
* On AWS, prefer the **Amazon SES (API)** mailer with an IAM role (see the SES
question below) — it removes the need to store any SMTP credentials at all.
### Can I send through Amazon SES without storing any credentials?
Yes. Custom SMTP includes an **Amazon SES (API)** mailer that authenticates through
your AWS **IAM role** (the ECS task role or EC2 instance role) using the AWS default
credential chain. You never enter or store an access key, secret key, or SMTP credential—
ideal for stateless, containerized WordPress on AWS ECS/Fargate.
In Settings > Custom SMTP, choose „Amazon SES (API · IAM role)“ as the mailer, set
the region and a verified sender address (or inject them as environment variables),
and you’re done. You can also provide a SES Configuration Set for bounce/complaint
tracking, and „Send Test Email“ returns the SES MessageId so you can confirm the
send on the AWS side.
The following environment variables / PHP constants take priority over the saved
settings, so the same container image works across environments:
* `SES_REGION` (falls back to `AWS_REGION`) — e.g. `eu-west-3`
* `SES_FROM_EMAIL` — the verified sender address
* `SES_CONFIG_SET` — optional SES configuration set
The message is sent as raw MIME, so HTML, attachments, CC/BCC, Reply-To and custom
headers are all preserved. The mailer works whether or not the AWS SDK for PHP is
installed (it falls back to a built-in signed API client), and SES sends are logged
in the Email Logs like any other email.
This is different from the existing **Amazon SES** SMTP preset, which uses SMTP
credentials — the new mailer uses the SES API and your IAM role instead.
### Can I configure everything from environment variables (config-as-code)?
Yes. Every setting can be forced from a PHP constant or environment variable, which
takes priority over the value saved in the database — ideal for immutable Docker
images and `DISALLOW_FILE_MODS` deployments.
Use `CUSTOM_SMTP_` in uppercase, for example:
* `CUSTOM_SMTP_MAILER_TYPE` — `smtp` or `ses_api`
* `CUSTOM_SMTP_HOST`, `CUSTOM_SMTP_PORT`, `CUSTOM_SMTP_SECURE`, `CUSTOM_SMTP_USERNAME`,`
CUSTOM_SMTP_PASSWORD`
* `CUSTOM_SMTP_MAILFROM`, `CUSTOM_SMTP_FROMNAME`, `CUSTOM_SMTP_LOG_RETENTION`
* `CUSTOM_SMTP_ALERTS_ENABLED`, `CUSTOM_SMTP_ALERT_EMAIL`, `CUSTOM_SMTP_ALERT_WEBHOOK`,`
CUSTOM_SMTP_ALERT_MAX_PER_HOUR`, `CUSTOM_SMTP_ALERT_MAX_PER_DAY`, `CUSTOM_SMTP_ALERT_COOLDOWN`
The Amazon SES shortcuts also apply: `SES_REGION` (or `AWS_REGION`), `SES_FROM_EMAIL`,`
SES_CONFIG_SET`.
An empty value counts as „not set“, so it never overrides anything. To force a boolean
setting off, give it an explicit value: `CUSTOM_SMTP_ALERTS_ENABLED=false` (or `
0`), not an empty string.
To switch an entire Multisite network to Amazon SES with no database changes, set
in your container: `CUSTOM_SMTP_MAILER_TYPE=ses_api`, `SES_REGION=eu-west-3`, `SES_FROM_EMAIL
=no-reply@example.com`.
Values are resolved from PHP constants, then `getenv()`, `$_ENV`, and `$_SERVER`.
The `$_SERVER` source means FrankenPHP (including worker mode) and Bedrock-style
stacks work with plain environment variables — no constants required.
On Multisite, the plugin also reads a network-wide option (via `get_site_option`)
beneath any per-site option, so a single configuration can apply to all sites. Fields
supplied by the environment are shown read-only in the settings page with a badge
naming the source variable. (A password supplied via `CUSTOM_SMTP_PASSWORD` is used
as-is; only stored passwords are encrypted at rest.)
### Can AI assistants or automation tools manage my SMTP?
Yes, on WordPress 6.9+. Custom SMTP registers two abilities with the WordPress Abilities
API:
* `custom-smtp/connection-health` returns the current SMTP state (configured, host,
port, encryption, auth, logging retention) — useful for diagnostics and monitoring.
* `custom-smtp/send-test-email` triggers a test email through the configured SMTP
server.
Both abilities are accessible to MCP-compatible AI clients, automation workflows(
n8n, Make), and other plugins. They enforce the same capability check as the wp-
admin interface (`manage_options`), so unprivileged users or scripts cannot invoke
them.
## Recenze
### [Ideal for solving problems with emails that are not sending (forms, etc.)](https://wordpress.org/support/topic/ideal-for-solving-problems-with-emails-that-are-not-sending-forms-etc/)
[jcsamalens](https://profiles.wordpress.org/jcsamalens/) 29. 9. 2024
This plugin is really simple but very useful to solve all the problems related to
php mail() function. I use it with Amazon SES but they work with any SMTP server.
It has fixed issues on many of my websites. And what’s more, it’s free, unlike the
others!
[ Přečtěte si 1 recenzi ](https://wordpress.org/support/plugin/custom-smtp/reviews/)
## Autoři
Custom SMTP: Email Deliverability – FREE & Easy-to-use je otevřený software. Následující
lidé přispěli k vývoji tohoto pluginu.
Spolupracovníci
* [ Nicolas Verlhiac ](https://profiles.wordpress.org/nicolasverlhiac/)
[Přeložte “Custom SMTP: Email Deliverability – FREE & Easy-to-use” do svého jazyka.](https://translate.wordpress.org/projects/wp-plugins/custom-smtp)
### Zajímá vás vývoj?
[Prohledejte kód](https://plugins.trac.wordpress.org/browser/custom-smtp/), podívejte
se do [SVN repozitáře](https://plugins.svn.wordpress.org/custom-smtp/), nebo se
přihlaste k[ odběru protokolu vývoje](https://plugins.trac.wordpress.org/log/custom-smtp/)
pomocí [RSS](https://plugins.trac.wordpress.org/log/custom-smtp/?limit=100&mode=stop_on_copy&format=rss).
## Přehled změn
#### 2.7.3
_Dead v1.x files removed from the package, translations unblocked_
* Removed the `includes/` directory inherited from version 1.x. Those files stopped
being loaded in 2.5 but were still shipped in the download. Nothing changes in
how the plugin works, the package is simply lighter and free of dead code.
* Translators can now finish their work. The plugin exposed 281 translatable strings,
of which 51 came from those leftover files and appeared nowhere in the interface.
Translating the entire visible plugin capped out at 82%, below the 90% WordPress.
org requires to build an official language pack. The project is now down to its
230 real strings, so the threshold is reachable: [translate.wordpress.org](https://translate.wordpress.org/projects/wp-plugins/custom-smtp/)
#### 2.7.2
_Scaleway provider preset, refreshed listing_
* New provider preset: **Scaleway** (Transactional Email). Selecting it fills the
SMTP relay (`smtp.tem.scaleway.com`, port 587, TLS); the [step-by-step guide](https://customsmtp.com/guides/scaleway/)
covers the unusual credentials (the username is your Project ID, the password
is the secret key of an API key) and the domain validation Scaleway requires
before the first email.
* Reorganized this plugin page: the description now follows the reader’s need (
provider, email log with preview and resend, alerts, WordPress notification switches)
with a single developers block at the end; the deep Amazon SES and config-as-
code material stays in the FAQ.
* First banners on the listing, in English and French, matching the site’s design.
#### 2.7.1
_Documentation links_
* The Documentation links in wp-admin now point to the documentation hub at [customsmtp.com/docs/](https://customsmtp.com/docs/),
and each provider preset links to its own step-by-step guide on customsmtp.com(
Gmail, Outlook, Amazon SES, SendGrid, Mailgun, Brevo, Postmark, Mailjet, Zoho,
Yahoo, iCloud) instead of the provider’s generic documentation. Each guide carries
the exact values the preset fills in and still links to the official provider
documentation.
* Completed the French translation: the settings screen, the email logs screen
and the test/error messages introduced in 2.x are now fully translated, and the
encryption level „None“ is now translatable.
#### 2.7.0
_Manage WordPress notifications_
* New **WordPress Notifications** section in the settings: switch off the emails
WordPress sends on its own, one by one, with no code.
* Covers the password reset notice to the administrator, the new user notice to
the administrator, the reports from automatic core, plugin and theme updates,
the comment awaiting moderation notice, and the new comment notice to the post
author.
* A notification you switch off is never created, so it does not appear in the
Email Logs either. The screen says so, to avoid hunting for an email you turned
off yourself.
* Emails your users need to keep control of their account, such as the password
reset link itself or the address change confirmation, are deliberately out of
reach: a settings screen should never be able to break account recovery.
* Nothing is switched off by default, so installing or updating the plugin never
silences an email your site was already sending.
* Each switch is a normal setting, so it can be forced from a PHP constant or environment
variable like everything else (`CUSTOM_SMTP_NOTIFY_ADMIN_PASSWORD_RESET` and
friends).
* Thanks to @aleksandreeu on the support forum for asking for this.
#### 2.6.1
_Fixes_
* **Fixed: the SMTP password was stored double-encrypted on the first save.** On
a site where the settings had never been saved before, WordPress ran the validation
callback twice and the password was encrypted a second time, so authentication
failed and „Test Connection“ reported an error until the settings were saved
again. Existing sites are unaffected; if you hit this, saving your password once
more is enough.
* **Fixed: concurrent alert checks could send the same alert several times.** The
lock guarding the periodic check was not atomic, so on a busy site several processes
could run it at once and each send its own email. It now relies on a single atomic
insert, and the inline failure rule is guarded the same way.
* Added two QA scripts under `bin/` (not shipped in the plugin) that replay the
alert and settings scenarios against a wp-env site with real assertions.
#### 2.6.0
_Unusual usage alerts_
* New **Unusual Usage Alerts** section in the settings: get warned when email activity
looks abnormal, either a sending spike (compromised form, runaway plugin) or
a delivery breakdown (revoked credentials, exhausted quota, relay down).
* **Volume rules** — alert above a configurable number of emails per hour and per
day. Thresholds are absolute rather than relative, so a low traffic site is never
alerted for what is only statistical noise.
* **Failure rules** — alert on consecutive failures (detected immediately, without
waiting for cron, and even when logging is disabled) and on too many failures
among the last emails sent. Counting over the last sends rather than over a time
window keeps the check meaningful on sites that send a couple of emails a week.
* **Three delivery channels** — email to the address of your choice (the site administrator
by default), an optional HTTPS webhook for Slack, Teams or any JSON endpoint,
and a persistent wp-admin notice. The webhook and the notice still work when
email delivery itself is the problem.
* **Cooldown** — a configurable delay before the same alert can fire again, so
an ongoing incident does not fill your inbox.
* The alert email is excluded from the logs and from its own thresholds, via the
new `custom_smtp_skip_log` filter.
* Every alert setting can be forced from a PHP constant or environment variable
like the rest of the configuration (`CUSTOM_SMTP_ALERTS_ENABLED`, `CUSTOM_SMTP_ALERT_MAX_PER_HOUR`,`
CUSTOM_SMTP_ALERT_WEBHOOK`, and so on).
* Alerts are **off by default**: enable them and adjust the thresholds to your
own traffic.
#### 2.5.0
_Resend failed emails from the logs_
* New **Resend** action on failed entries in the Email Logs: re-send a message
that didn’t go through (e.g. after fixing your SMTP/SES configuration) directly
from wp-admin, without having to trigger the original action again.
* The resend goes through your currently configured mailer (SMTP or Amazon SES)
and is captured as a new log entry.
* Recipient, subject, body and headers are reconstructed from the stored log. The
Resend action appears only on failed entries whose body was stored — enabling**
Store email content** is what makes a failed email replayable. Attachments are
not stored, so they are not included (the confirmation dialog notes this when
the entry had attachments).
#### 2.4.1
_Environment compatibility_
* Constant / environment overrides are now also read from `$_SERVER`, where FrankenPHP(
worker mode, where `getenv()` is unreliable) and Bedrock-style setups expose
environment variables reliably — enabling 100% env-var configuration on those
stacks without declaring PHP constants. Resolution order: constant `getenv()``
$_ENV` `$_SERVER`. Only the plugin’s fixed variable names are read, and client
request headers (which land in `$_SERVER` as `HTTP_*` keys) cannot spoof them.
#### 2.4.0
_Config-as-code: constant/env overrides for every setting + Multisite network settings_
**Config-as-code**
* Every setting can now be forced from a PHP constant or environment
variable, taking priority over the database value — built for immutable images and`
DISALLOW_FILE_MODS`. Use `CUSTOM_SMTP_` (e.g. `CUSTOM_SMTP_MAILER_TYPE`,`
CUSTOM_SMTP_HOST`, `CUSTOM_SMTP_LOG_RETENTION`). * The mailer selection (`mailer_type`)
is now overridable — set `CUSTOM_SMTP_MAILER_TYPE=ses_api` to activate Amazon SES
across a whole site or network with no per-site configuration and no custom `option_*`
filter. * The existing Amazon SES shortcuts (`SES_REGION` / `AWS_REGION`, `SES_FROM_EMAIL`,`
SES_CONFIG_SET`) continue to work and now sit in the same unified override system.*
Settings supplied by the environment are shown read-only in wp-admin with a „from`
VARIABLE`“ badge so the source is visible.
**Multisite**
* On a network, settings are read from the network-wide option (`
get_site_option`) beneath any per-site option, so one configuration can apply to
all sites.
**Note**
* SMTP passwords supplied via `CUSTOM_SMTP_PASSWORD` are used as-is (not
decrypted) — only stored passwords are encrypted at rest.
#### 2.3.0
_New mailer: Amazon SES API with IAM role authentication_
**New Feature — Amazon SES (API) mailer**
* New mailer type that sends through
the Amazon SESv2 API instead of SMTP, authenticated **exclusively** by the server’s
AWS IAM role (ECS task role / EC2 instance role) via the AWS default credential
chain — **no access keys, secret keys, or SMTP credentials** are stored or required.*
Built for stateless, containerized WordPress on AWS (ECS/Fargate): no secrets in
the database, following 12-factor principles. * Full message fidelity — HTML, attachments,
CC/BCC, Reply-To and custom headers are preserved (sent as raw MIME); BCC recipients
are delivered via the SES envelope and stay hidden. * Optional **SES Configuration
Set** support for bounce/complaint tracking and CloudWatch metrics. * Region, sender
address and configuration set can be injected via environment variables / constants(`
SES_REGION` / `AWS_REGION`, `SES_FROM_EMAIL`, `SES_CONFIG_SET`), overriding the
stored settings — so the same image runs across environments. * Dependency-free —
uses the AWS SDK for PHP when present, otherwise a built-in SigV4-signed API client
over the WordPress HTTP API (nothing to bundle). * „Send Test Email“ returns the
SES MessageId on success. * SES sends are captured by the Email Logs (status, content
preview) just like SMTP sends. * Note: this is distinct from the existing **Amazon
SES** SMTP preset, which uses SMTP credentials. The new mailer uses the SES API
and IAM roles.
#### 2.2.1
_Documentation update_
* Surfaced the Abilities API integration (shipped in 2.2.0) in the plugin description
and FAQ — users can now discover the AI / workflow capabilities directly from
the WordPress.org plugin page without digging into the changelog.
* Added dedicated **Deliverability** section highlighting SPF/DKIM alignment, PHPMailer
7.0.2 compatibility, and UTF-8/emoji handling.
* Added dedicated **Privacy & GDPR-friendly** section listing the existing privacy
mitigations (encryption at rest, automatic log purge, opt-out content storage,
sandboxed preview).
* Mentioned the English / French translations and the „built for modern WordPress“
stance in the intro.
* Fixed the Installation steps: removed an incorrect „by WPForms“ mention and refreshed
the provider preset list to match the 11 presets actually shipped (Gmail, Outlook,
AWS SES, SendGrid, Mailgun, Brevo, Postmark, Mailjet, Zoho, Yahoo, iCloud).
* Refreshed the WordPress.org tags (`smtp, email, deliverability, mail logger,
email logger`) to better reflect the plugin’s positioning.
* No functional changes.
#### 2.2.0
_WordPress 7 compatibility release_
**WordPress 7 Compatibility**
* Verified compatibility with WordPress 7.0 and PHPMailer
7.0.2 (no code changes required — plugin uses only public PHPMailer properties and
methods). * Cooperates with the automatic Envelope-From / Return-Path behavior introduced
in WordPress 6.9, so SPF/DKIM alignment now works correctly on strict hosts without
manual configuration. * Added a contextual note under the From Email field explaining
the new envelope sender behavior on WordPress 6.9+.
**New Integration**
* Abilities API support (WordPress 6.9+): two server-side abilities
are now exposed for AI assistants, dashboards, and workflow tools. * `custom-smtp/
connection-health` — returns whether SMTP is configured, host, port, encryption
mode, auth state, and log retention. * `custom-smtp/send-test-email` — sends a test
email through the configured SMTP server.
**Changed Defaults**
* **Store Email Content** is now enabled by default on new
installs so the log preview is useful out of the box. Existing installs keep their
saved preference. You can still disable it from the Email Logging settings card;
with the default log retention of 30 days, stored bodies are automatically purged.
**Also Included (from the 2.1.0 line)**
* iCloud Mail provider preset. * Documented
stateless and cloud-ready compatibility (Docker, Kubernetes, ECS/Fargate, Cloud
Run, Bedrock, Trellis). * Removed legacy v1.x procedural code; the v2.x OOP architecture
is now the single source of truth.
#### 2.1.0
_Release Date – May 26, 2026_
**New Features**
* Provider Presets: One-click configuration for Gmail, Outlook,
AWS SES, SendGrid, Mailgun, Brevo, Postmark, Mailjet, Zoho, Yahoo, and iCloud. *
Auto-fill settings: Select a provider and Host, Port, Encryption, Authentication
are automatically configured. * Documentation links: Quick access to each provider’s
SMTP documentation.
**UI Improvements**
* Redesigned settings page with card-based layout. * Status
bar showing SMTP configuration state at a glance. * Collapsible Advanced Settings
section. * Save button in each settings card for quick access. * Responsive design
for mobile admin access.
**Documentation**
* Documented stateless and cloud-ready compatibility (Docker,
Kubernetes, ECS/Fargate, Cloud Run, Bedrock, Trellis). * Expanded FAQ with the full
list of supported SMTP providers.
**Maintenance**
* Removed legacy v1.x procedural code; the v2.x OOP architecture
is now the single source of truth.
#### 2.0.0
_Release Date – February 4, 2026_
**Major Release – Architecture Refactor & Email Logging**
**New Features**
* Email Logging: Track all sent emails with recipient, subject,
date/time, and status (success/failed). * Email Logs Dashboard: View all logged
emails with search, filters, and pagination. * Email Preview Sidebar: View full
email content in an Outlook-style sidebar panel. * Email Content Storage: Optionally
store complete email body for later preview (disabled by default for privacy). *
Download Email: Export any logged email as HTML file for archiving or debugging.*
Date Range Filters: Quick filters for Today, Last 7 days, Last 30 days. * CSV Export:
Export email logs to CSV for reporting and analysis. * Auto-purge: Configurable
log retention (default 30 days) with automatic cleanup. * Statistics Bar: Compact
inline stats showing total, sent, failed, and today’s email counts. * Refresh Button:
One-click refresh of email logs.
**Architecture**
* Complete OOP refactor with PSR-4 namespaces (CustomSMTP\). *
Dependency injection pattern for better testability. * Separated concerns: Plugin,
Settings, Mailer, Logger, Encryption classes. * Custom database table for email
logs.
**Security**
* Email preview uses sandboxed iframe (no JavaScript execution). *
Email body limited to 500KB to prevent database bloat. * All AJAX actions protected
with nonce verification and capability checks.
**Improved**
* Cleaner, more maintainable codebase. * Better separation of admin
UI and core functionality. * Enhanced error handling throughout. * Responsive design
for mobile admin access.
**Note**
* All v1.x settings are preserved and compatible. * Email logging is enabled
by default (can be disabled in settings). * Email content storage is disabled by
default – enable in settings to use preview feature.
#### 1.9.0
_Release Date – December 5, 2025_
**Security**
* SMTP password is now encrypted in the database using AES-256-CBC
with WordPress salts. * Password field no longer displays the stored value (shows
placeholder instead).
**Added**
* New „Test Connection“ button to verify SMTP settings without sending
an email. * New „SMTP Authentication“ option (Yes/No) to support relay servers without
authentication. * Improved error messages: common PHPMailer errors are now translated
to user-friendly messages.
**Changed**
* Test buttons now show „Test Connection“ and „Send Test Email“ separately.*
Password field shows „Leave empty to keep current password“ when a password is already
saved.
**Note**
* Existing plaintext passwords will continue to work and will be encrypted
on next save.
#### 1.8.1
_Release Date – December 5, 2025_
**Fixed**
* WordPress 6.9 compatibility: Use `wp_mail_from` filter instead of setting
From in `phpmailer_init` (fixes „Invalid address“ error). * Fixed test email button
not working due to duplicate PHPMailer hooks.
**Changed**
* **Breaking:** „Mail From“ field moved from Optional to Main settings(
now required for WordPress 6.9+). * Test button now auto-saves settings before sending
test email. * Improved error messages: shows which required fields are missing. *
Disabled SMTPAutoTLS when security is set to „None“ (fixes Mailpit/local testing).
#### 1.8.0
_Release Date – December 4, 2025_
**Fixed**
* WordPress 6.9 compatibility: Fixed email sending failure with AWS SES
and other SMTP providers that require verified sender addresses. * Added proper
Envelope-From (Sender/Return-Path) configuration to comply with WordPress 6.9 PHPMailer
changes. * Test emails now correctly use the configured „Mail From“ address as the
envelope sender.
**Changed**
* Minimum WordPress version updated to 6.0. * Minimum PHP version updated
to 7.4.
**Note**
* Users must configure the „Mail From“ field in optional settings with
a verified email address (especially important for AWS SES users).
#### 1.7
_Release Date – July 5, 2024_
**Improved**
* Improved security of saved options with appropriate validation and
sanitization. * Code optimization by removing unused code comments and adding value
checks before use. * Split the main custom-smtp.php file into several files to improve
maintainability and readability. * Creation of includes/admin, includes/smtp and
includes/utils folders to organize code by functionality.
**Fixed**
* Fixed validation of `secure` options to ensure they are either `none`,`
ssl` or `tls`. * Translations : Test email.
#### 1.6
_Release Date – April 3, 2024_
* New optional settings for all emails sent by WordPress:
- Addition of „Reply To“ option: This feature allows you to specify an email
address that recipients will send replies to, instead of the original sender’s
email address. This is useful when the sender does not wish to receive replies
directly.
- Addition of „CC“ option: „CC“ stands for „Carbon Copy“. When you CC an email
to someone, you send them a copy of your email. The CC’d person may not be
the main recipient of the email, but they are included for their reference.
Everyone who receives the email can see who has been CC’d.
- Addition of „BCC“ option: „BCC“ stands for „Blind Carbon Copy“. This works
like CC, but BCC recipients are hidden from the other recipients. This is
useful when you want to inform someone without letting others know that they
are also receiving the same email.
* Incompatible plugin detection: This feature helps identify any plugins that are
not compatible and could potentially cause issues (proactive approach to prevent
conflicts). It will alert you if an installed plugin is not compatible with the
Custom SMTP plugin, allowing you to take necessary action.
* Comprehensive test email with configuration information
#### 1.5
_Release Date – March 14, 2024_
* You can test your SMTP settings before saving them.
* Secure SMTP option accept `None` as value.
* Custom CSS for Settings.
#### 1.4
_Release Date – March 12, 2024_
* Public launch of the plugin!
* Completely translated into English and French.
* All SMTP options are editable.
## Meta
* Verze **2.7.3**
* Poslední aktualizace **před 1 týdnem**
* Aktivních instalací **100+**
* Verze WordPressu ** 6.0 nebo novější **
* Testováno až do WordPressu **7.0.3**
* Verze PHP ** 7.4 nebo novější **
* Jazyk
* [English (US)](https://wordpress.org/plugins/custom-smtp/)
* Štítků
* [deliverability](https://cs.wordpress.org/plugins/tags/deliverability/)[email](https://cs.wordpress.org/plugins/tags/email/)
[email logger](https://cs.wordpress.org/plugins/tags/email-logger/)[mail logger](https://cs.wordpress.org/plugins/tags/mail-logger/)
[smtp](https://cs.wordpress.org/plugins/tags/smtp/)
* [Podrobnosti](https://cs.wordpress.org/plugins/custom-smtp/advanced/)
## Hodnocení
5 z 5 hvězdiček.
* [ 1 5hvězdičkové hodnocení ](https://wordpress.org/support/plugin/custom-smtp/reviews/?filter=5)
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* [ 0 3hvězdičkové hodnocení ](https://wordpress.org/support/plugin/custom-smtp/reviews/?filter=3)
* [ 0 2hvězdičkové hodnocení ](https://wordpress.org/support/plugin/custom-smtp/reviews/?filter=2)
* [ 0 1hvězdičkové hodnocení ](https://wordpress.org/support/plugin/custom-smtp/reviews/?filter=1)
[Your review](https://wordpress.org/support/plugin/custom-smtp/reviews/#new-post)
[Zobrazit všechny recenze](https://wordpress.org/support/plugin/custom-smtp/reviews/)
## Spolupracovníci
* [ Nicolas Verlhiac ](https://profiles.wordpress.org/nicolasverlhiac/)
## Podpora
Vyřešené problémy během posledních dvou měsíců:
1 z 1
[Fórum podpory](https://wordpress.org/support/plugin/custom-smtp/)