Title: Lettr &#8211; Email API
Author: vojtechj
Published: <strong>2026-05-19</strong>
Last modified: 2026-05-19

---

Szukaj wtyczek

![](https://s.w.org/plugins/geopattern-icon/lettr.svg)

# Lettr – Email API

 Autor: [vojtechj](https://profiles.wordpress.org/vojtechj/)

[Pobierz](https://downloads.wordpress.org/plugin/lettr.1.0.0.zip)

 * [Szczegóły](https://pl.wordpress.org/plugins/lettr/#description)
 * [Recenzje](https://pl.wordpress.org/plugins/lettr/#reviews)
 *  [Instalacja](https://pl.wordpress.org/plugins/lettr/#installation)
 * [Rozwój](https://pl.wordpress.org/plugins/lettr/#developers)

 [Wsparcie](https://wordpress.org/support/plugin/lettr/)

## Opis

Send transactional and marketing emails from your WordPress site using the [Lettr](https://lettr.com)
email API. Lettr replaces the default WordPress email system with a reliable, developer-
friendly API that delivers emails to inboxes — not spam folders.

#### Why Lettr?

 * **Reliable email delivery** — Built on battle-tested infrastructure with SPF,
   DKIM, and DMARC authentication out of the box.
 * **Simple setup** — Connect your WordPress site with a single API key. No SMTP
   configuration needed.
 * **Transactional email at scale** — Send password resets, order confirmations,
   notifications, and more through the Lettr email API.
 * **Real-time tracking** — Monitor opens, clicks, bounces, and deliverability from
   the Lettr dashboard.
 * **Templates & personalization** — Use the Lettr drag-and-drop editor and merge
   tags for dynamic content.
 * **Developer-first** — RESTful API, detailed documentation, and SDKs for PHP, 
   Node.js, Python, Go, Rust, Java, and Laravel.

#### How it works

This plugin overrides the default WordPress `wp_mail()` function and routes all 
outgoing emails through the Lettr API. This means every email your site sends — 
including emails from WooCommerce, contact form plugins, and any other plugin — 
is delivered through Lettr automatically.

#### Links

 * [Lettr Website](https://lettr.com)
 * [Documentation](https://docs.lettr.com)
 * [API Reference](https://docs.lettr.com/api-reference/introduction)

### External services

This plugin connects to the Lettr API at `app.lettr.com` to deliver email on behalf
of your WordPress site. Each time `wp_mail()` is invoked, the plugin sends the following
data to Lettr over HTTPS so that Lettr can process and deliver the message:

 * The configured sender email address and name
 * Recipient, CC, BCC, and Reply-To addresses
 * The email subject, HTML and/or plain text body, and any attachments
 * Any custom email headers, tags, or metadata supplied by the calling code
 * Your Lettr API key (sent as a Bearer token in the `Authorization` header for 
   authentication)

The plugin also calls `app.lettr.com/api/auth/check` to validate the API key when
you save it on the settings screen.

This service is provided by Lettr. By using this plugin you agree to Lettr’s terms
and acknowledge their privacy practices:

 * Terms of Service: [https://lettr.com/terms](https://lettr.com/terms)
 * Privacy Policy: [https://lettr.com/privacy-policy](https://lettr.com/privacy-policy)

## Instalacja

 1. Upload the plugin to `/wp-content/plugins/lettr` or install via the WordPress plugin
    installer.
 2. Activate the plugin through the **Plugins** menu.
 3. Go to **Settings  Lettr** and enter your API key from the [Lettr dashboard](https://lettr.com).
 4. Configure your sender name and email address.
 5. Send a test email to verify everything is working.

## Najczęściej zadawane pytania

### Do I need a Lettr account?

Yes. Sign up for free at [lettr.com](https://lettr.com) to get your API key.

### Does this work with WooCommerce?

Yes. Lettr handles all emails sent via the standard WordPress `wp_mail()` function,
which includes WooCommerce order confirmations, shipping notifications, and customer
emails.

### Do I need to configure SMTP?

No. Lettr uses a REST API instead of SMTP, which means there are no ports to open
or SMTP credentials to manage.

### Where can I find my API key?

Log in to your account at [lettr.com](https://lettr.com) and navigate to the API
Keys section.

## Recenzje

Wtyczka nie ma jeszcze żadnej recenzji.

## Kontrybutorzy i deweloperzy

„Lettr – Email API” jest oprogramowaniem open source. Poniższe osoby miały wkład
w rozwój wtyczki.

Zaangażowani

 *   [ vojtechj ](https://profiles.wordpress.org/vojtechj/)

[Przetłumacz wtyczkę “Lettr – Email API” na swój język.](https://translate.wordpress.org/projects/wp-plugins/lettr)

### Interesuje cię rozwój wtyczki?

[Przeglądaj kod](https://plugins.trac.wordpress.org/browser/lettr/), sprawdź [repozytorium SVN](https://plugins.svn.wordpress.org/lettr/)
lub czytaj [dziennik rozwoju](https://plugins.trac.wordpress.org/log/lettr/) przez
[RSS](https://plugins.trac.wordpress.org/log/lettr/?limit=100&mode=stop_on_copy&format=rss).

## Rejestr zmian

#### 1.0.0

 * Initial release.

## Meta

 *  Wersja **1.0.0**
 *  Ostatnia aktualizacja **1 tydzień temu**
 *  Włączone instalacje **Mniej niż 10**
 *  Wersja WordPressa ** 5.8 lub nowszej **
 *  Testowano do **6.9.4**
 *  Wersja PHP ** 7.2 lub nowszej **
 *  Język
 * [English (US)](https://wordpress.org/plugins/lettr/)
 * Tagi
 * [email](https://pl.wordpress.org/plugins/tags/email/)[Email API](https://pl.wordpress.org/plugins/tags/email-api/)
   [smtp](https://pl.wordpress.org/plugins/tags/smtp/)[transactional email](https://pl.wordpress.org/plugins/tags/transactional-email/)
 *  [Widok zaawansowany](https://pl.wordpress.org/plugins/lettr/advanced/)

## Oceny

Nie przesłano jeszcze żadnych recenzji.

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

[Zobacz wszystkierecenzje.](https://wordpress.org/support/plugin/lettr/reviews/)

## Zaangażowani

 *   [ vojtechj ](https://profiles.wordpress.org/vojtechj/)

## Wsparcie

Masz coś do dodania? Potrzebujesz pomocy?

 [Zobacz forum wsparcia](https://wordpress.org/support/plugin/lettr/)