The official Go library for ClickSend v3 API

This is the official ClickSend Go SDK. Documentation can be found here.

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Requirements

• Go 1.18 or later
• A free ClickSend account — sign up here
• Your ClickSend username (email) and API key from the API Credentials page

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Installation

Step 1 — Verify Go is installed

go version

You should see output like go version go1.21.0 darwin/arm64. If not, install Go first.

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Step 2 — Create a new project directory

mkdir clicksend-sms && cd clicksend-sms

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Step 3 — Initialise a Go module

go mod init clicksend-sms

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Step 4 — Install the ClickSend Go SDK

go get github.com/ClickSend/clicksend-go

Run go mod tidy to pull in all transitive dependencies:

go mod tidy

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Step 5 — Create main.go

Create a file named main.go in your project directory and paste the following code:

package main

import (
	"context"
	"fmt"
	"log"

	clicksend "github.com/ClickSend/clicksend-go"
)

const (
	username = "USERNAME"  // Your ClickSend username (email)
	apiKey   = "API_KEY"   // Your ClickSend API key
	fromNum  = "FROM"      // Approved sender ID or number e.g. "+61400000000"
	toNum    = "TO"        // Recipient number in E.164 format e.g. "+61400000001"
)

func main() {
	cfg := clicksend.NewConfiguration()
	client := clicksend.NewAPIClient(cfg)

	auth := context.WithValue(context.Background(), clicksend.ContextBasicAuth, clicksend.BasicAuth{
		UserName: username,
		Password: apiKey,
	})

	msg := clicksend.SmsMessage{
		From:   fromNum,
		To:     toNum,
		Body:   "Hello from the ClickSend Go SDK!",
		Source: "go-sdk",
	}

	result, _, err := client.SMSApi.SmsSendPost(auth, clicksend.SmsMessageCollection{
		Messages: []clicksend.SmsMessage{msg},
	})
	if err != nil {
		log.Fatalf("error sending SMS: %v", err)
	}

	fmt.Println("Response:", result)
}

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Step 6 — Set your credentials

Replace the four constants at the top of main.go with your actual values:

Constant	Where to find it
USERNAME	Your ClickSend account email
API_KEY	Dashboard → API Credentials
FROM	An approved sender ID or your ClickSend number (leave blank to use a shared number)
TO	The destination phone number in E.164 format e.g. +61400000001

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Step 7 — Run the code

go run main.go

A successful response looks like this:

{
  "http_code": 200,
  "response_code": "SUCCESS",
  "response_msg": "Messages queued for delivery.",
  "data": {
    "total_price": 0.891,
    "total_count": 1,
    "queued_count": 1,
    "messages": [
      {
        "status": "SUCCESS",
        "message_id": "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx",
        "to": "+61400000001",
        "from": "ClickSend",
        "body": "Hello from the ClickSend Go SDK!"
      }
    ]
  }
}

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Project Structure

clicksend-sms/
├── main.go    # Example — send a single SMS
├── go.mod     # Module definition and SDK dependency
└── go.sum     # Dependency checksums

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Authentication

The SDK uses HTTP Basic Auth. Your username and API key are passed via context on every request:

auth := context.WithValue(context.Background(), clicksend.ContextBasicAuth, clicksend.BasicAuth{
    UserName: "your_username",
    Password: "your_api_key",
})

Pass this auth context as the first argument to every API call.

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Sending to Multiple Recipients

Pass more than one SmsMessage in the Messages slice to send in a single API call (up to 1 000 messages per request):

result, _, err := client.SMSApi.SmsSendPost(auth, clicksend.SmsMessageCollection{
    Messages: []clicksend.SmsMessage{
        {From: fromNum, To: "+61400000001", Body: "Hello Alice!", Source: "go-sdk"},
        {From: fromNum, To: "+61400000002", Body: "Hello Bob!",   Source: "go-sdk"},
    },
})

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Further Reading

• ClickSend REST API docs
• clicksend-go SDK on GitHub
• ClickSend Dashboard