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 keyfromNum="FROM"// Approved sender ID or number e.g. "+61400000000"toNum="TO"// Recipient number in E.164 format e.g. "+61400000001"
)
funcmain() {
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},
})
iferr!=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