feat: added smtp support to email

.env.example

@@ -15,4 +15,16 @@ CONCURRENCY="10"
 NEXT_PUBLIC_DASHBOARD_URL="http://localhost:3000"
 NEXT_PUBLIC_API_URL="http://localhost:3333"
 WORKER_PORT=9999
-API_PORT=3333
+API_PORT=3333
+
+# EMAIL - set one or both; SMTP takes priority over Resend if SMTP_HOST is set
+# Option A - Resend
+# RESEND_API_KEY=""
+# EMAIL_SENDER="hello@openpanel.dev"
+# Option B - SMTP (used first when SMTP_HOST is present, even if RESEND_API_KEY is also set)
+# SMTP_HOST=""
+# SMTP_PORT="587"
+# SMTP_SECURE="false"
+# SMTP_USER=""
+# SMTP_PASS=""
+# EMAIL_SENDER="hello@openpanel.dev"

apps/public/content/docs/self-hosting/environment-variables.mdx

@@ -324,15 +324,85 @@ Get your API key from [resend.com](https://resend.com). Make sure to verify your
 **Required**: No  
 **Default**: `hello@openpanel.dev`
 
-Email address used as the sender for transactional emails.
+Email address used as the sender for transactional emails. Applies to both Resend and SMTP transports.
 
 **Example**:
 ```bash
 EMAIL_SENDER=noreply@yourdomain.com
 ```
 
+### SMTP_HOST
+
+**Type**: `string`  
+**Required**: No  
+**Default**: None
+
+SMTP server hostname. When set, OpenPanel uses SMTP to send emails instead of Resend. Takes priority over `RESEND_API_KEY` if both are configured.
+
+**Example**:
+```bash
+SMTP_HOST=smtp.example.com
+```
+
+### SMTP_PORT
+
+**Type**: `number`  
+**Required**: No  
+**Default**: `587`
+
+SMTP server port.
+
+**Example**:
+```bash
+SMTP_PORT=587
+```
+
+### SMTP_SECURE
+
+**Type**: `boolean`  
+**Required**: No  
+**Default**: `false`
+
+Use TLS for the SMTP connection. Set to `true` when using port `465`.
+
+**Example**:
+```bash
+SMTP_SECURE=true
+```
+
+### SMTP_USER
+
+**Type**: `string`  
+**Required**: No  
+**Default**: None
+
+SMTP authentication username. Leave unset if your server does not require authentication.
+
+**Example**:
+```bash
+SMTP_USER=smtp-user@example.com
+```
+
+### SMTP_PASS
+
+**Type**: `string`  
+**Required**: No  
+**Default**: None
+
+SMTP authentication password.
+
+**Example**:
+```bash
+SMTP_PASS=your-smtp-password
+```
+
 <Callout>
-The sender email must be verified in your Resend account.
+Set `SMTP_HOST` to enable SMTP. If both `SMTP_HOST` and `RESEND_API_KEY` are present, SMTP takes priority. If neither is set, emails are logged to the console (useful for development).
+In case of using Resend, the sender email must be verified in your Resend account.
+</Callout>
+
+<Callout type="warn">
+If `SMTP_HOST` is set and an SMTP send attempt fails, the system will **not** automatically fall back to `RESEND_API_KEY` — the email will be silently dropped. To use Resend instead, unset `SMTP_HOST`.
 </Callout>
 
 ## OAuth & Integrations
@@ -834,7 +904,7 @@ For a basic self-hosted installation, these variables are required:
 
 ### Optional but Recommended
 
-- `RESEND_API_KEY` - For email features
+- `RESEND_API_KEY` or `SMTP_HOST` - For email features (pick one)
 - `EMAIL_SENDER` - Email sender address
 - `OPENAI_API_KEY` and/or `ANTHROPIC_API_KEY` - For the in-app AI chat assistant
 

apps/public/content/docs/self-hosting/self-hosting.mdx

@@ -102,7 +102,7 @@ const op = new OpenPanel({
 
 ### E-mail
 
-Some of OpenPanel's features require e-mail. We use Resend as our transactional e-mail provider. To enable email features, create an account on Resend and set the `RESEND_API_KEY` environment variable.
+Some of OpenPanel's features require e-mail. We use Resend as our transactional e-mail provider by default, but you can also use your own SMTP server. To enable email features, set the relevant environment variables described below.
 
 <Callout>This is nothing that is required for the basic setup, but it is required for some features.</Callout>
 
@@ -112,6 +112,32 @@ Features that require e-mail:
 - Invitations
 - more will be added over time
 
+#### Option A — Resend
+
+Create an account on [resend.com](https://resend.com), verify your sender domain, and set the `RESEND_API_KEY` environment variable.
+
+```bash title=".env"
+RESEND_API_KEY=re_xxxxxxxxxxxxx
+EMAIL_SENDER=noreply@yourdomain.com
+```
+
+#### Option B — SMTP
+
+If you prefer to use your own SMTP server, set `SMTP_HOST` and OpenPanel will use it instead of Resend.
+
+```bash title=".env"
+SMTP_HOST=smtp.example.com
+SMTP_PORT=587
+SMTP_SECURE=false
+SMTP_USER=smtp-user@example.com
+SMTP_PASS=your-smtp-password
+EMAIL_SENDER=noreply@yourdomain.com
+```
+
+<Callout type="info">
+`SMTP_HOST` takes priority over `RESEND_API_KEY` if both are set. If neither is configured, emails are logged to the console instead of being sent.
+</Callout>
+
 For email configuration details, see the [Environment Variables documentation](/docs/self-hosting/environment-variables#email).
 
 ### AI integration

packages/email/package.json

@@ -10,6 +10,9 @@
   "dependencies": {
     "@openpanel/db": "workspace:*",
     "@react-email/components": "^0.5.6",
+    "@react-email/render": "^2.0.7",
+    "@types/nodemailer": "^8.0.0",
+    "nodemailer": "^8.0.5",
     "react": "catalog:",
     "react-dom": "catalog:",
     "resend": "^4.0.1",

packages/email/src/index.tsx

@@ -1,4 +1,6 @@
 import React from 'react';
+import { render } from '@react-email/render';
+import { createTransport } from 'nodemailer';
 import { Resend } from 'resend';
 import type { z } from 'zod';
 
@@ -13,6 +15,21 @@ const FROM = process.env.EMAIL_SENDER ?? 'hello@openpanel.dev';
 export type EmailData<T extends TemplateKey> = z.infer<Templates[T]['schema']>;
 export type EmailTemplate = keyof Templates;
 
+function createSmtpTransport() {
+  return createTransport({
+    host: process.env.SMTP_HOST,
+    port: process.env.SMTP_PORT ? Number(process.env.SMTP_PORT) : 587,
+    secure: process.env.SMTP_SECURE === 'true',
+    auth:
+      process.env.SMTP_USER && process.env.SMTP_PASS
+        ? { user: process.env.SMTP_USER, pass: process.env.SMTP_PASS }
+        : undefined,
+    connectionTimeout: 10_000,
+    greetingTimeout: 10_000,
+    socketTimeout: 30_000,
+  });
+}
+
 export async function sendEmail<T extends TemplateKey>(
   templateKey: T,
   options: {
@@ -47,30 +64,52 @@ export async function sendEmail<T extends TemplateKey>(
     }
   }
 
+  const headers: Record<string, string> = {};
+  if ('category' in template && template.category) {
+    const unsubscribeUrl = getUnsubscribeUrl(to, template.category);
+    (props.data as any).unsubscribeUrl = unsubscribeUrl;
+    headers['List-Unsubscribe'] = `<${unsubscribeUrl}>`;
+    headers['List-Unsubscribe-Post'] = 'List-Unsubscribe=One-Click';
+  }
+
+  const subject = template.subject(props.data as any);
+
+  if (process.env.SMTP_HOST) {
+    try {
+      const html = await render(
+        <template.Component {...(props.data as any)} />,
+      );
+      const transport = createSmtpTransport();
+      const res = await transport.sendMail({
+        from: FROM,
+        to,
+        subject,
+        html,
+        headers,
+      });
+      return res;
+    } catch (error) {
+      console.error('Failed to send email via SMTP', error);
+      return null;
+    }
+  }
+
   if (!process.env.RESEND_API_KEY) {
-    console.log('No RESEND_API_KEY found, here is the data');
+    console.log('No SMTP_HOST or RESEND_API_KEY found, here is the data');
     console.log('Template:', template);
-    console.log('Subject: ', template.subject(props.data as any));
+    console.log('Subject: ', subject);
     console.log('To:      ', to);
     console.log('Data:    ', JSON.stringify(data, null, 2));
     return null;
   }
 
   const resend = new Resend(process.env.RESEND_API_KEY);
 
-  const headers: Record<string, string> = {};
-  if ('category' in template && template.category) {
-    const unsubscribeUrl = getUnsubscribeUrl(to, template.category);
-    (props.data as any).unsubscribeUrl = unsubscribeUrl;
-    headers['List-Unsubscribe'] = `<${unsubscribeUrl}>`;
-    headers['List-Unsubscribe-Post'] = 'List-Unsubscribe=One-Click';
-  }
-
   try {
     const res = await resend.emails.send({
       from: FROM,
       to,
-      subject: template.subject(props.data as any),
+      subject,
       react: <template.Component {...(props.data as any)} />,
       headers: Object.keys(headers).length > 0 ? headers : undefined,
     });
@@ -79,7 +118,7 @@ export async function sendEmail<T extends TemplateKey>(
     }
     return res;
   } catch (error) {
-    console.error('Failed to send email', error);
+    console.error('Failed to send email via Resend', error);
     return null;
   }
 }