Contact API

Deployable multi-provider contact form API

Table of Contents

• Features
• Usage
• Response
• Deployment & Configuration
  • Prerequisites
  • Configure .env
  • Deploying
  • Local Development
• License

Features

• Single POST /api/contact endpoint - drop into any project.
• Multi-provider support: Resend and Nodemailer (SMTP).
• CORS support via ALLOWED_ORIGINS.
• Input validation with descriptive error responses.
• Rate limiting via Vercel WAF to prevent spam and abuse.
• Honeypot protection.

Note: To utilize the honeypot, include a hidden input field named fax_number in your frontend and keep it empty when submitting the form.

Usage

await fetch("https://your-deployment.vercel.app/api/contact", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
        email: "sender@example.com",  // required
        message: "Your message here", // required
        subject: "Hello",             // optional
        name: "Your name",            // optional
        fax_number: ""                // optional; must be empty
    })
});

Response

Status	Body
200	{ success: true, message: "Message sent successfully" }
400	{ error: "Invalid or missing fields" }
403	{ error: "Forbidden" }
405	{ error: "Method not allowed" }
415	{ error: "Unsupported Media Type" }
429	{ error: "Too many requests. Please try again later" }
500	{ error: "Message delivery failed. Please try again later" }
503	{ error: "Service temporarily unavailable" }

Deployment & Configuration

Prerequisites

• Node.js 20+
• Vercel
• An email provider
  • Resend: API key and verified domain.
  • Nodemailer: Valid SMTP settings (host, port, auth.user, auth.pass, and secure when needed).

1. Clone & Install

git clone https://github.com/masonlet/contact-api.git
cd contact-api
npm install

2. Configure .env

Copy .env.example to .env and fill Environment Variables. Shared values are required; provider-specific values depend on EMAIL_PROVIDER.

Variable	Description
FROM_EMAIL	Sender address
TO_EMAIL	Recipient email addresses, comma-separated.
ALLOWED_ORIGINS	Allowed CORS origins, comma-separated. Leave empty to block all cross-origin requests.
EMAIL_PROVIDER	Email provider to use: resend or nodemailer.
RESEND_API_KEY	Resend API key, required when EMAIL_PROVIDER=resend.
SMTP_CONFIG	JSON string of Nodemailer SMTP config, required when EMAIL_PROVIDER=nodemailer.

Deploying

Deploy with Vercel

Deploy with Nodemailer

Local Development

npm run typecheck     # TypeScript type check
npm run test          # Run Vitest tests
npm run test:watch    # Run Vitest in watch mode
npm run test:coverage # Run Vitest in coverage mode

License

MIT License - see LICENSE for details.