Title: Lettr &#8211; Email API
Author: vojtechj
Published: <strong>19 Μαΐου  2026</strong>
Last modified: 22 Σεπτεμβρίου  2026

---

Αναζήτηση πρόσθετων

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

# Lettr – Email API

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

[Λήψη](https://downloads.wordpress.org/plugin/lettr.1.5.0.zip)

 * [Λεπτομέρειες](https://el.wordpress.org/plugins/lettr/#description)
 * [Κριτικές](https://el.wordpress.org/plugins/lettr/#reviews)
 *  [Εγκατάσταση](https://el.wordpress.org/plugins/lettr/#installation)
 * [Ανάπτυξη](https://el.wordpress.org/plugins/lettr/#developers)

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

## Περιγραφή

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)

## Εγκατάσταση

 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.

## Συχνές Ερωτήσεις

### 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.

## Κριτικές

Δεν υπάρχουν αξιολογήσεις για αυτό το πρόσθετο.

## Συνεισφέροντες & Προγραμματιστές

“Lettr – Email API” είναι λογισμικό ανοιχτού κώδικα. Οι παρακάτω έχουν συνεισφέρει
στη δημιουργία του.

Συντελεστές

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

[Μεταφράστε το “Lettr – Email API” στην γλώσσα σας.](https://translate.wordpress.org/projects/wp-plugins/lettr)

### Ενδιαφέρεστε για την ανάπτυξη;

[Περιηγηθείτε στον κώδικα](https://plugins.trac.wordpress.org/browser/lettr/), ανατρέξτε
στο [αποθετήριο SVN](https://plugins.svn.wordpress.org/lettr/) ή εγγραφείτε στο 
[αρχείο καταγραφής αλλαγών ανάπτυξης](https://plugins.trac.wordpress.org/log/lettr/)
μέσω [RSS](https://plugins.trac.wordpress.org/log/lettr/?limit=100&mode=stop_on_copy&format=rss).

## Σύνοψη αλλαγών

#### 1.5.0

 * Add `list_scheduled_emails()` — the emails waiting to be sent, filterable by `
   status` (`scheduled`, `sending`, `sent`, `cancelled`, `failed`). This is the 
   only way to find a scheduled email whose id was not kept.
 * `get_scheduled_email()` and `cancel_scheduled_email()` now take a `$request_id`—
   Lettr’s own id, prefixed `sch_`. Lettr holds a scheduled email itself rather 
   than handing it straight to the sending provider, so the provider’s `transmission_id`
   is a _different_ value: it stays null until the email actually sends, and it 
   is the id webhook events carry. Passing it where a request id belongs is a 404.
   The parameter was renamed to say which one it wants; positional callers are unaffected.
 * Cancelling now answers with the cancelled email rather than an empty body, and
   scheduling accepts a delivery time up to 30 days out, up from 3.

#### 1.4.0

 * Add `list_folders()` — the folders templates are filed into, with each folder’s
   purpose and template count. Nothing else in the API returns a folder id, so without
   it a caller either omits `folder_id` and accepts whichever folder the API picks,
   or hardcodes an integer read out of an app URL.
 * `create_template()` accepts `purpose` (`transactional` or `campaign`), and `list_templates()`
   accepts `purpose` and `folder_id` filters. A campaign can only send a template
   whose purpose is `campaign`, and the purpose cannot be changed after creation.
 * Add the `lettr_idempotency_key` filter. Return a stable string and a retried `
   wp_mail()` replays the original send instead of delivering a second email. Opt-
   in by design: deriving a key from the payload would silently collapse two legitimately
   identical notifications into one. `Lettr_Api::send_email()` also takes the key
   as a second argument.
 * Template responses now carry `preparation_status` (`pending`, `ready`, `failed`)—
   documented; no client change was needed, since responses pass through decoded.

#### 1.3.0

 * Add bulk topic subscription API client methods (`bulk_subscribe_audience_contacts_to_topics`,`
   bulk_unsubscribe_audience_contacts_from_topics`).
 * `bulk_create_audience_contacts()` now documents the per-contact `contacts` request
   shape, the batch-wide `list_ids` / `topics` / `update_existing` options, and 
   the `updated` / `error_count` / `errors` / `contacts` response fields. No call
   signature changed — existing payloads send exactly as before.
 * **Behaviour change from the Lettr API:** creating a contact whose email already
   exists now returns HTTP 409, so `create_audience_contact()` fails with a `WP_Error`
   code of `lettr_api_resource_already_exists` (status 409). It previously returned
   HTTP 500, i.e. `lettr_api_send_error` (status 500). Custom code branching on 
   the old code no longer matches, and a 409 here must not be retried.

#### 1.2.0

 * Add campaigns API client methods (list, show, events, send, schedule, unschedule).

#### 1.1.0

 * Add audience API client methods (lists, contacts, topics, properties, segments).
 * Bump tested-up-to to WordPress 7.0.

#### 1.0.0

 * Initial release.

## Μεταστοιχεία

 *  Version **1.5.0**
 *  Τελευταία ενημέρωση: **πριν από 6 ημέρες**
 *  Ενεργές εγκαταστάσεις: **Λιγότερες από 10**
 *  Έκδοση WordPress: ** 5.8 ή νεότερη **
 *  Δοκιμασμένο μέχρι: **7.0.6**
 *  Έκδοση PHP: ** 7.2 ή νεότερη **
 *  Language
 * [English (US)](https://wordpress.org/plugins/lettr/)
 * Ετικέτες:
 * [email](https://el.wordpress.org/plugins/tags/email/)[Email API](https://el.wordpress.org/plugins/tags/email-api/)
   [smtp](https://el.wordpress.org/plugins/tags/smtp/)[transactional email](https://el.wordpress.org/plugins/tags/transactional-email/)
 *  [Σύνθετη Προβολή](https://el.wordpress.org/plugins/lettr/advanced/)

## Αξιολογήσεις

No reviews have been submitted yet.

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

[See all reviews](https://wordpress.org/support/plugin/lettr/reviews/)

## Συντελεστές

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

## Υποστήριξη

Έχετε κάτι να πείτε; Χρειάζεστε βοήθεια;

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