Resend API

api.resend.com · Communication

Communication Bearer Token Free Tier Email Transactional Email Communication

Modern developer-first email API — send transactional emails with React, HTML, or plain text. Clean REST API, excellent DX. Free tier: 100 emails/day, 3,000/month.

Authentication

Bearer Token Free API key at resend.com. Pass as Authorization: Bearer YOUR_KEY.

Sample Requests

POST Send email

Send an HTML email with Resend.

https://api.resend.com/emails

Hover any highlighted part to learn what it does

Headers — extra info sent with the request

Content-Type	application/json
Authorization	Bearer YOUR_KEY

Request Body — data you're sending

{
  "to": [
    "[email protected]"
  ],
  "from": "[email protected]",
  "html": "<p>Hello from <strong>Resend</strong>!</p>",
  "subject": "Hello World"
}

curl -X POST "https://api.resend.com/emails" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"to":["[email protected]"],"from":"[email protected]","html":"<p>Hello from <strong>Resend</strong>!</p>","subject":"Hello World"}'

import requests
headers = {
    "Content-Type": "application/json",
    "Authorization": "Bearer YOUR_ACCESS_TOKEN"
}
data = {
    "to": [
        "[email protected]"
    ],
    "from": "[email protected]",
    "html": "<p>Hello from <strong>Resend</strong>!</p>",
    "subject": "Hello World"
}
response = requests.post(
    "https://api.resend.com/emails",
    headers=headers,
    json=data,
)
print(response.json())

const url = 'https://api.resend.com/emails';

const response = await fetch(url, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': 'Bearer YOUR_ACCESS_TOKEN'
  },
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
  "to": [
    "[email protected]"
  ],
  "from": "[email protected]",
  "html": "<p>Hello from <strong>Resend</strong>!</p>",
  "subject": "Hello World"
}),
}); 
const data = await response.json();
console.log(data);

package main

import (
	"fmt"
	"io"
	"net/http"
	"bytes"
	"encoding/json"
)

func main() {
	targetURL := "https://api.resend.com/emails"
	jsonData, _ := json.Marshal({"to":["[email protected]"],"from":"[email protected]","html":"<p>Hello from <strong>Resend</strong>!</p>","subject":"Hello World"})
	req, _ := http.NewRequest("POST", targetURL, bytes.NewBuffer(jsonData))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer YOUR_ACCESS_TOKEN")
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{}
	resp, _ := client.Do(req)
	defer resp.Body.Close()
	body, _ := io.ReadAll(resp.Body)
	fmt.Println(string(body))
}

require "net/http"
require "json"

uri = URI("https://api.resend.com/emails")

http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == "https"

req = Net::HTTP::Post.new(uri)
req["Content-Type"] = "application/json"
req["Authorization"] = "Bearer YOUR_ACCESS_TOKEN"
req["Content-Type"] = "application/json"
req.body = "{\"to\":[\"[email protected]\"],\"from\":\"[email protected]\",\"html\":\"<p>Hello from <strong>Resend</strong>!</p>\",\"subject\":\"Hello World\"}"

res = http.request(req)
puts JSON.parse(res.body)

<?php
$url = "https://api.resend.com/emails";
$opts = ["http" => [
    "method" => "POST",
    "header" => implode("\r\n", [
        "Content-Type: application/json",
        "Authorization: Bearer YOUR_ACCESS_TOKEN",
        "Content-Type: application/json"
    ]),
    "content" => json_encode({"to":["[email protected]"],"from":"[email protected]","html":"<p>Hello from <strong>Resend</strong>!</p>","subject":"Hello World"}),
]];
$ctx = stream_context_create($opts);
$res = file_get_contents($url, false, $ctx);
print_r(json_decode($res, true));

Postman Setup Guide

Get Postman ↗

Sign up at resend.com — free tier: 3,000 emails/month
Get API key from resend.com/api-keys
Set Authorization: Bearer YOUR_KEY
from must be from a verified domain (or use [email protected] for testing)
Works great with React Email for templating

Open documentation ↗