Resolving SMTP Issues with Nodemailer on Vercel

Isanes Francois
Saturday, June 1, 2024 at 8:15:42 AM
JavaScript (Next.js)

Resolving Email Issues in Production

When your app is deployed on Vercel, are you having problems with Nodemailer? Even though everything functions flawlessly in your local environment, unforeseen mistakes might occasionally arise when moving to production.

We will go over typical problems and how to fix them in this article, with a particular emphasis on the reasons why your SMTP email configuration might not work on Vercel even when it functions properly locally. Now let's investigate and resolve these issues.

Command Description
NextRequest Access to incoming request data is made possible by this representation of the request object in Next.js API routes.
NextResponse Used to build response objects for Next.js API routes so that JSON responses may be sent.
nodemailer.createTransport Sets up a transport object so that Nodemailer can send emails via SMTP.
transport.sendMail Uses the transport object made with nodemailer to send an email.makeTransport.
await request.json() Uses an async function to extract JSON data from the incoming request.
fetch Carries out HTTP requests, such as those made to an API endpoint to deliver form data.
useState Handy for processing form inputs, this React functional component manages state.

Recognizing the Fix for Nodemailer Problems

The included backend script is made to manage email sending via a Next.js API route with for a contact form. The script retrieves the email, name, and message from the request body of a POST request performed to this endpoint. It then uses these details to create an HTML email content. is used to create the transport object, providing the host, port, and login credentials for the SMTP server.

is called with the email settings to send the email after the transport is configured. A JSON response indicating success is returned if the operation is successful; if not, an error message is sent back. Using the command and a POST request, the function on the frontend delivers the form data to the API endpoint. useState is used to record and update form input data in the state. The function initiates the email sending process upon form submission, guaranteeing a seamless user experience.

Backend Code: Next, take care of the Nodemailer setup.js

JavaScript (Next.js API Route)

import { type NextRequest, NextResponse } from 'next/server';
import nodemailer from 'nodemailer';

export async function POST(request: NextRequest) {
  try {
    const { email, name, message } = await request.json();

    const htmlContent = `
      <html>
        <head>
          <style>
            body {
              font-family: Arial, sans-serif;
              font-size: 16px;
            }
            .container {
              max-width: 600px;
              margin: 0 auto;
            }
            .subject {
              color: #b02d1f;
              margin-bottom: 20px;
            }
          </style>
        </head>
        <body>
          <div class="container">
            <h2 class="subject">Fresh Communication via the Contact Form</h2>
            <p><strong>Name:</strong> ${name}
            <p><strong>Email:</strong> ${email}
            <p><strong>Message:</strong> ${message}
          </div>
        </body>
      </html>`;

    const transport = nodemailer.createTransport({
      host: "example.prod.iad2.secureserver.net",
      port: 465,
      secure: true,
      auth: {
        user: process.env.MY_EMAIL,
        pass: process.env.MY_PASSWORD,
      },
    });

    const mailOptions = {
      from: process.env.MY_EMAIL,
      to: process.env.MY_EMAIL,
      subject: `New Message from ${name} (${email})`,
      html: htmlContent,
      replyTo: email,
    };

    await new Promise((resolve, reject) => {
      transport.sendMail(mailOptions, function (err) {
        if (!err) {
          resolve('Email sent!');
        } else {
          reject(err);
        }
      });
    });

    return NextResponse.json({ message: 'Email sent' });
  } catch (err) {
    return NextResponse.json({ error: err.message || "An error occurred" }, { status: 500 });
  }
}

Frontend Code: Using a Contact Form to Send Email

JavaScript (React)

import { FormData } from '@/components/ContactForm';

export function sendEmail(data: FormData) {
  const apiEndpoint = '/api/email';

  fetch(apiEndpoint, {
    method: 'POST',
    body: JSON.stringify(data),
  })
    .then((res) => res.json())
    .catch((err) => console.error("Error sending email:", err));
}

// Example of how to use sendEmail function:
import { useState } from 'react';
import { sendEmail } from '@/utils/send-email';

export default function ContactForm() {
  const [formData, setFormData] = useState({ name: '', email: '', message: '' });

  const handleChange = (e) => {
    const { name, value } = e.target;
    setFormData({ ...formData, [name]: value });
  };

  const handleSubmit = (e) => {
    e.preventDefault();
    sendEmail(formData);
  };

  return (
    <form onSubmit={handleSubmit}>
      <input name="name" value={formData.name} onChange={handleChange} />
      <input name="email" value={formData.email} onChange={handleChange} />
      <textarea name="message" value={formData.message} onChange={handleChange} />
      <button type="submit">Send</button>
    </form>
  );
}

Maintaining an Appropriate Environment Adaptable Setup

The correct setting of environment variables in the production environment is an important factor that is frequently disregarded when addressing problems similar to the one that has been mentioned. While environment variables are typically easily accessible in local development environments via a.env file, deploying to a service such as Vercel necessitates proper configuration of these variables in the platform's settings. This guarantees that private data, such login passwords, is safely stored and available to your program while it is running.

You must go to your project settings and enter the necessary variables under the 'Environment Variables' section in order to establish environment variables on Vercel. Verify that the environment variable names exactly correspond to the ones you've used in your code. This step is essential for the smooth operation of features like using Nodemailer to send emails through SMTP servers.

  1. Why does my Vercel email not function while it works locally?
  2. Make sure Vercel has your environment variables configured appropriately. Verify the authentication and SMTP configuration information.
  3. On Vercel, how can I set environment variables?
  4. Navigate to the 'Environment Variables' area of your Vercel project settings, and enter your variables there.
  5. What are the typical production-related problems with Nodemailer?
  6. Erroneous environment variables, improperly configured SMTP settings, and network limitations are common causes of problems.
  7. Can I use Nodemailer with any SMTP server?
  8. Yes, provided that you have the proper host, port, and login information configured.
  9. How can my email API's 500 error be troubleshooted?
  10. Make sure all configurations and dependencies are configured appropriately, and keep an eye out for specific error messages in the server logs.
  11. Which email transmission best practices are secure?
  12. For sensitive data, use environment variables; for secure connections (SSL/TLS), properly authenticate your email server.
  13. Should I set up my local and production environments differently?
  14. Make that environment-specific configurations are applied correctly in production, even though the setup can be comparable.
  15. Is there an email sending program other than Nodemailer?
  16. Indeed, there are more choices. SendGrid, Mailgun, and AWS SES are reliable APIs for delivering emails.
  17. How come my email is flagged as spam?
  18. Make that the email content is formatted correctly, that the headers are correct, and that the SPF/DKIM records for your sending domain are correct.
  19. Can I use Nodemailer in production with Gmail?
  20. Yes, you can use Gmail; but, to improve security, you should use OAuth2 or enable less secure apps. You can also configure Gmail with an app password.

In conclusion, a few crucial actions must be taken in order to fix the problem where Nodemailer functions locally but not on Vercel. Make sure that Vercel's settings have your environment variables set up appropriately. Check that the host, port, and authentication credentials for your SMTP server are correct. You should no longer get the 500 issue in the production build after taking these steps. Your contact form should work flawlessly in both local and production contexts with the right configuration and close attention to detail, giving your application dependable communication capabilities.