Resend — Modern Email API for Developers

What it is

Resend is a developer-first email API that makes sending transactional emails simple. It supports React Email templates for building emails with components, provides webhooks for delivery tracking, and handles deliverability concerns (SPF, DKIM, DMARC) out of the box. The project has 15,000+ GitHub stars and SDKs for Node.js, Python, Ruby, Go, and more.

Resend targets developers building applications that send transactional emails: welcome messages, password resets, order confirmations, and notifications. It replaces legacy email services with a modern API that treats email templates as code.

How it saves time or tokens

Resend eliminates the complexity of email infrastructure. SPF, DKIM, and DMARC configuration is handled automatically. React Email templates let you build emails with components and props rather than writing raw HTML with inline styles. Webhooks provide delivery, open, and click tracking without bolting on a separate analytics service. The result is email functionality that takes 3 lines of code instead of a week of infrastructure setup.

How to use

1. Install the SDK:

npm install resend

1. Send an email:

import { Resend } from 'resend';

const resend = new Resend('re_your_api_key');

await resend.emails.send({
  from: 'you@yourdomain.com',
  to: 'user@example.com',
  subject: 'Welcome!',
  html: '<h1>Welcome to our app!</h1>',
});

1. Get your API key at resend.com.

Example

Using React Email templates for structured email content:

import { Resend } from 'resend';
import { WelcomeEmail } from './emails/welcome';

const resend = new Resend('re_your_api_key');

await resend.emails.send({
  from: 'onboarding@yourdomain.com',
  to: 'user@example.com',
  subject: 'Welcome to the platform',
  react: WelcomeEmail({ userName: 'Alice', planName: 'Pro' }),
});

React Email templates render to cross-client HTML automatically, handling the quirks of Outlook, Gmail, and Apple Mail.

Related on TokRepo

• AI Tools for API — API services and SDKs for application development
• AI Tools for Automation — Automation tools for email workflows and notifications

Common pitfalls

• You must verify your sending domain with DNS records before sending. Unverified domains are rejected by Resend.
• The free tier has a daily sending limit. Production applications with high email volume need a paid plan.
• React Email templates require server-side rendering. They cannot be used directly in client-side React applications.
• Always check the official documentation for the latest version-specific changes and migration guides before upgrading in production environments.
• For team deployments, establish clear guidelines on configuration and usage patterns to ensure consistency across developers.