resend/references/installation.md

Resend SDK Installation Guide

Always install the latest SDK version to ensure you have support for all features including webhook verification (webhooks.verify()), email receiving (emails.receiving.get()), and domain claiming (domains.claims.*). Older versions may not include these methods.

Minimum SDK Versions

These are the minimum versions required for full functionality (sending, receiving, and webhook verification). Always prefer the latest version when possible.

Language	Package	Min Version	Install
Node.js	resend	>= 6.14.0	npm install resend
Python	resend	>= 2.34.0	pip install resend
Go	resend-go/v3	>= 3.11.0	go get github.com/resend/resend-go/v3
Ruby	resend	>= 1.6.0	gem install resend
PHP	resend/resend-php	>= 1.1.0	composer require resend/resend-php
Rust	resend-rs	>= 0.26.1	cargo add resend-rs
Java	resend-java	>= 4.16.0	See Maven/Gradle below
.NET	Resend	>= 0.2.1	dotnet add package Resend

If the project already has a Resend SDK installed, check the version and upgrade if it's below the minimum. Older SDKs may be missing webhooks.verify(), emails.receiving.get(), or domains.claims.*, which power webhook security, inbound email, and domain claiming.

Detecting Project Language

Check for these files to determine the project's language/framework:

File	Language	SDK
package.json	Node.js/TypeScript	resend
requirements.txt or pyproject.toml	Python	resend
go.mod	Go	resend-go/v3
Gemfile	Ruby	resend
composer.json	PHP	resend/resend-php
Cargo.toml	Rust	resend-rs
pom.xml or build.gradle	Java	resend-java
*.csproj or *.sln	.NET	Resend
mix.exs	Elixir	resend

Installation Commands

Node.js

npm install resend

Alternative package managers:

yarn add resend
pnpm add resend
bun add resend

Python

pip install resend

Go

go get github.com/resend/resend-go/v3

Ruby

gem install resend

Or add to Gemfile:

gem 'resend'

PHP

composer require resend/resend-php

Rust

cargo add resend-rs
cargo add tokio -F macros,rt-multi-thread

Java

Gradle:

implementation 'com.resend:resend-java:4.16.0'

Maven:

<dependency>
  <groupId>com.resend</groupId>
  <artifactId>resend-java</artifactId>
  <version>4.16.0</version>
</dependency>

.NET

dotnet add package Resend

Elixir

Add to mix.exs:

def deps do
  [
    {:resend, "~> 0.4.0"}
  ]
end

API Key Setup

All SDKs require a Resend API key. Get one at https://resend.com/api-keys

Recommended: Store API key in environment variable RESEND_API_KEY rather than hardcoding.

cURL (No SDK)

For quick tests or languages without an SDK, use the REST API directly:

curl -X POST 'https://api.resend.com/emails' \
  -H 'Authorization: Bearer re_xxxxxxxxx' \
  -H 'Content-Type: application/json' \
  -d '{
    "from": "Acme <[email protected]>",
    "to": ["[email protected]"],
    "subject": "hello world",
    "html": "<p>it works!</p>"
  }'