<p>Hey everyone,</p>
<p>I’ve been working on <strong>RustMailer</strong> for the past year, but until now I held off posting here because I felt it was missing key features and I needed to make frequent breaking changes to iterate quickly.</p>
<p>Today, I’m <strong>happy to announce RustMailer 1.0</strong>! 🎉</p>
<p>There are still a ton of things I’d like to build, but the project is now in a place where I feel more confident sharing it with the <strong>r/selfhosted</strong> community.</p>
<hr>
<h2>🌟 Key Features</h2>
<h3>🌐 Modern APIs</h3>
<ul>
<li>Offers both <strong>gRPC</strong> and <strong>OpenAPI</strong> interfaces</li>
<li>Multi-version API documentation</li>
</ul>
<h3>🚀 High Performance &amp; Cost-Efficient</h3>
<ul>
<li>Written in <strong>Rust</strong> for safety and speed</li>
<li>Low memory usage, <strong>no Redis or external dependencies required</strong></li>
<li>Ideal for production at minimal cost</li>
</ul>
<h3>📬 Multi-account IMAP Support</h3>
<ul>
<li>Incremental sync using <strong>UID-based strategy</strong></li>
<li>Supports <strong>folder selection</strong></li>
<li><strong>Windowed</strong> or <strong>date-range</strong> sync</li>
</ul>
<h3>📤 SMTP Sending</h3>
<ul>
<li>Manage outgoing email via SMTP</li>
<li>Connection pooling for better performance</li>
</ul>
<h3>🧾 Email Template Support</h3>
<ul>
<li>Dynamic templates for <strong>transactional</strong> and <strong>marketing</strong> messages</li>
</ul>
<h3>📡 Flexible MTA Integration</h3>
<ul>
<li>Send via <strong>account-specific SMTP servers</strong></li>
<li>Or use self-hosted MTA services / third-party providers</li>
</ul>
<h3>📈 Open &amp; Click Tracking</h3>
<ul>
<li>Built-in support for tracking <strong>email opens</strong> and <strong>link clicks</strong></li>
</ul>
<h3>🔄 Webhooks with VRL</h3>
<ul>
<li>Send webhook payloads to external systems</li>
<li>Process them with <strong>VRL scripts</strong> for filtering and transformation</li>
</ul>
<h3>🔌 NATS Integration</h3>
<ul>
<li>Push <strong>real-time events</strong> to NATS for seamless downstream integration</li>
</ul>
<h3>🖥️ Web UI &amp; Client</h3>
<ul>
<li>Built-in <strong>web-based email client</strong> and admin dashboard</li>
</ul>
<h3>🔐 OAuth2 Support</h3>
<ul>
<li>Built-in OAuth2 flow with <strong>web-based authorization UI</strong></li>
<li>Automatically manages <strong>access &amp; refresh tokens</strong></li>
</ul>
<h3>🌍 Proxy Support</h3>
<ul>
<li>IMAP, SMTP, and OAuth2 proxy support for restricted environments</li>
</ul>
<hr>
<h2>📦 Deployment</h2>
<ul>
<li><strong>Single sub-60MB binary</strong></li>
<li>Zero external dependencies (<strong>not even Redis</strong>)</li>
<li>No database required<br>
➡ Just run it and go.</li>
</ul>
<p>💡 <strong>License &amp; Pricing</strong><br>
RustMailer is <strong>not free</strong>. A <strong>free trial</strong> is available for testing and evaluation, but <strong>production use requires purchasing a license key</strong>.</p>
<hr>
<h2>❓ Why RustMailer?</h2>
<p>Most languages have IMAP/SMTP libraries – but they’re just <strong>low-level tools</strong>, not a production-ready email infrastructure.</p>
<p>To build a truly reliable email service, you need:<br>
✓ Incremental sync (with state tracking)<br>
✓ Battle-tested MIME parsing (BODYSTRUCTURE, encoding, attachments)<br>
✓ SMTP with deliverability (retries, DKIM, SPF, inbox placement)<br>
✓ Search across folders &amp; accounts (unified search, no IMAP limits)<br>
✓ Webhooks &amp; event-driven tasks (idempotency, retries, scaling)<br>
✓ Templates &amp; batch operations (without hitting rate limits)<br>
✓ Flaky IMAP recovery (because servers love to disconnect)</p>
<hr>
<h2>💪 What RustMailer Delivers</h2>
<ul>
<li>🚀 <strong>Massive-scale sync</strong> — 100s of accounts, zero manual management</li>
<li>🔍 <strong>Instant cross-account search</strong> — no IMAP roundtrips</li>
<li>⚡ <strong>Eventhooks API</strong> — extend functionality without modifying core logic</li>
<li>📦 Still just <strong>one &lt;60MB binary</strong> — no DB, no Redis, no containers needed</li>
</ul>
<hr>
<p>If you find this useful, I’d really appreciate a ⭐ on GitHub — it helps more developers discover the project!</p>

Self-hosted refers to the practice of running your own applications and services on your own servers or devices, giving you full control over your data and how it is managed.

selfhosted

RustMailer 1.0 is a self-hosted email middleware written in Rust that provides IMAP/SMTP functionality through modern APIs. It offers multi-account IMAP sync, SMTP sending, email templates, tracking capabilities, webhooks with VRL processing, and NATS integration. The solution comes as a single 60MB binary with no external dependencies like Redis or databases, making it cost-efficient for production deployment. It includes OAuth2 support, proxy capabilities, and a built-in web UI. The software requires a paid license for production use but offers a free trial.

RustMailer: A Self-Hosted IMAP/SMTP Middleware for Developers

<p>Hi everyone! I’m curious about the community’s thoughts on self-hosted email tools.</p>
<p>If you could improve one thing in your current setup, what would it be?</p>
<p>Your feedback would be super helpful for shaping RustMailer’s next updates. 🚀</p>


<p>Is this an alternative to Emailengine?</p>


<p><a href="https://github.com/rustmailer/rustmailer" target="_blank" rel="noopener nofollow">https://github.com/rustmailer/rustmailer</a></p>


<p>I would love to contribute to it and use on my home lap. Can you provide the github link</p>


<p>RustMailer, because the most important aspect of your application is the language it’s written in.</p>
