Tahhan JMAP Mailer

Tahhan JMAP Mailer replaces WordPress’s built-in mailer with the modern JMAP protocol (RFC 8620 / RFC 8621). JMAP is the successor to IMAP and SMTP, designed from scratch for the modern web. It communicates over standard HTTPS, works through firewalls and NAT without any special port configuration, and is natively supported by leading mail servers such as Stalwart Mail Server, Fastmail, and Cyrus IMAP.

Unlike SMTP plugins that require relay credentials, third-party services, or open ports, Tahhan JMAP Mailer connects directly to your own JMAP-capable mail server using HTTP Basic authentication over an encrypted HTTPS connection. well-known/jmap — no manual API URL configuration needed.

Tahhan JMAP Mailer is built as a proper WordPress plugin: it uses wp_remote_get/post, WP_Error, WordPress nonces, and the standard sanitization and escaping APIs throughout. There are zero external PHP dependencies. It hooks into pre_wp_mail to intercept every wp_mail() call site-wide and deliver the email through a two-step JMAP pipeline: Email/set to create the email object, followed by EmailSubmission/set to submit it for delivery.

Every send attempt is logged (recipient, subject, status, JMAP IDs) in a capped mail log — message bodies are never stored. The plugin ships with a full admin UI including a setup wizard, live connection testing, multi-account management, conditional routing rules, a retry queue with exponential backoff, open tracking, CSV log export, and WooCommerce email type detection.

Features

• JMAP Protocol — Full RFC 8620 / RFC 8621 implementation, two-step Email/set + EmailSubmission/set delivery

• Auto-discovery — JMAP session discovered automatically from /.well-known/jmap

• Multi-account — Configure multiple JMAP accounts (Primary, Transactional, etc.)

• Advanced routing rules — Route emails based on recipient domain/email (with wildcard and regex support), subject, body, attachments, or plugin type. Override the From address and set a fallback account per rule

• Retry queue — Failed sends automatically retried via WP-Cron with exponential backoff

• Open tracking — Optional 1×1 pixel tracking for HTML emails, entirely self-hosted

• WooCommerce integration — Detect and route WooCommerce order, customer, and admin emails

• Mail log — Last 100 send attempts with recipient, subject, status, JMAP IDs, error details

• CSV export — Download the full mail log as a CSV file

• Multiple identities — Per-account JMAP sending identities with auto-resolve support

• Setup wizard — Guided first-time configuration with step-by-step instructions

• Live connection testing — AJAX-based JMAP session test with step-by-step feedback

• No external dependencies — Zero third-party PHP libraries required

Compatible Servers

Tahhan JMAP Mailer works with any mail server that implements RFC 8621 (JMAP for Mail):

• Stalwart Mail Server — Full JMAP support, recommended for self-hosted setups

• Fastmail — Full JMAP support, commercial hosted service

• Cyrus IMAP — Full JMAP support, enterprise self-hosted

• Apache James — Full JMAP support, open source Java-based server

• Any RFC 8621-compliant server — The plugin uses only standard JMAP capabilities