Active installationsNewAdoption metric — not a quality score
WordPress.org ratingNo WordPress.org ratings yet
Official packageDirect from WordPress.org
Repository metrics are context, not quality scores. Active installations measure adoption and can strongly reflect a plugin’s age and historical popularity. Ratings, recent updates and “Tested up to” metadata also do not guarantee modern code, error-free operation, security, feature completeness or suitability for a particular site. Why active installs don’t tell the whole story →
WP PlugIndex currently records Lettr – Email API version 1.5.0 as active, updated 1mo ago and tested up to WordPress 7.0.
Overview
About this plugin
Send transactional and marketing emails from your WordPress site using the Lettr 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
Documentation
API Reference
External services
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)
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
Privacy Policy: https://lettr.com/privacy-policy
WordPress.org metadata
Plugin tags
Topics listed for this plugin in the WordPress.org directory.
email api
transactional email
lettr
smtp
Compatibility & maintenance
Compatibility & maintenance
Tested up to WordPress 7.0
Not yet marked as tested with WordPress 7.1. WordPress.org currently lists Tested up to 7.0.
Current WordPress releaseWordPress 7.1
WordPress.org Tested up to7.0
Minimum requirementsWordPress 5.8 · PHP 7.2
Update activity22 Sept 20261mo ago
“Tested up to” is directory metadata supplied by the plugin author. WP PlugIndex does not turn an older declaration into a claim that the plugin is incompatible.
Changes recorded by WP PlugIndex
Recent tracked changes
Version1.4.0→1.5.0
WordPress compatibility7.0.4→7.0.5
Version1.3.0→1.4.0
Tracking & source
WP PlugIndex tracks public WordPress.org directory metadata and records selected version, compatibility and availability changes as they are detected.
