Installation

Add the Resend Go SDK to your project

Get the Resend Go SDK installed and configured in your Go application.

Requirements

Before installing the SDK, ensure your environment meets these requirements:

• Go 1.23 or later - The SDK requires Go 1.23+
• Go modules - The SDK uses Go modules for dependency management

Install the SDK

1. Install via go get

   Add the Resend Go SDK to your project using the go get command:

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

   This downloads the SDK and adds it to your go.mod file.

2. Import the package

   Import the Resend package in your Go files:

   import "github.com/resend/resend-go/v3"
   

   Make sure to use the /v3 suffix in the import path to get the latest version of the SDK.

3. Verify installation

   Create a simple file to verify the installation:

   package main
   
   import (
       "fmt"
       "github.com/resend/resend-go/v3"
   )
   
   func main() {
       client := resend.NewClient("your_api_key")
       fmt.Println("Resend client initialized successfully")
   }
   

   Run the file to confirm everything is working:

   go run main.go
   

   You should see the success message printed to the console.

Package structure

The Resend Go SDK is organized into service-based modules:

package main

import "github.com/resend/resend-go/v3"

func main() {
    client := resend.NewClient("re_123")

    // Access different services through the client
    client.Emails       // Send and manage emails
    client.Batch        // Send batch emails
    client.Domains      // Manage domains
    client.ApiKeys      // Manage API keys
    client.Contacts     // Manage contacts
    client.Segments     // Manage segments (audiences)
    client.Broadcasts   // Send broadcasts
    client.Templates    // Manage email templates
    client.Topics       // Manage topics
    client.Webhooks     // Manage webhooks
}

Dependencies

The SDK has minimal dependencies. The only testing dependency is:

• github.com/stretchr/testify - Used for testing (not required in production)

All other dependencies are part of the Go standard library.

Custom HTTP client

By default, the SDK uses a standard HTTP client with a 1-minute timeout. You can provide your own HTTP client for custom configurations:

package main

import (
    "net/http"
    "time"
    "github.com/resend/resend-go/v3"
)

func main() {
    // Create custom HTTP client
    httpClient := &http.Client{
        Timeout: 30 * time.Second,
    }

    // Initialize Resend with custom client
    client := resend.NewCustomClient(httpClient, "re_123")
}

This is useful when you need to:

• Configure custom timeouts
• Add retry logic
• Use custom transport layers
• Implement request/response logging

Environment configuration

The SDK reads the RESEND_BASE_URL environment variable if you need to use a custom API endpoint. This is typically only needed for testing or enterprise configurations.

Next steps

Now that you have the SDK installed, you’re ready to send your first email:

Quickstart

Learn how to send your first email with the Resend Go SDK