Sendgo authentication is two steps: exchange keys for a token, send with the token.

Most of the time you never need this page — the SDKs handle all of it. It matters when you call REST directly or build a client for a language with no SDK.

What you need

An accessKey and secretKey from Integration → Apps in the Sendgo console.

export SENDGO_ACCESS_KEY=your_access_key
export SENDGO_SECRET_KEY=your_secret_key

These carry the full sending permission for the account. Do not commit them. If you already did, revoking and reissuing in the console is the only fix — reverting the commit does not un-leak anything.

Issue a token

Base64-encode accessKey:secretKey and send it as Basic auth.

curl -X POST https://sendgo.io/api/v2/token \
  -H "Authorization: Basic $(printf '%s:%s' "$SENDGO_ACCESS_KEY" "$SENDGO_SECRET_KEY" | base64)"

{
  "data": {
    "token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
  }
}

Call with the token

Everything after this uses bearer auth, and v1 and v2 differ.

Version	Header
v1	Authorization: Bearer base64(token)
v2	Authorization: Bearer token

Forgetting the second encode on v1 gives you a 401. Use v2.

curl -X POST https://sendgo.io/api/v2/notices/send \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "templateCode": "ORDER_CONFIRM_001",
    "scheduleType": "DIRECTLY",
    "kakaoSenderKey": "your_kakao_sender_key",
    "senderKey": "your_sms_sender_key",
    "contacts": [{ "contact": "01012345678", "var1": "ORD-001" }]
  }'

With an SDK

Pass the keys and stop thinking about it. Issuance, caching, refresh on expiry and the 401/403 retry all happen inside.

import Sendgo from '@sendgo/node';

const sendgo = new Sendgo({
  accessKey:  process.env.SENDGO_ACCESS_KEY!,
  secretKey:  process.env.SENDGO_SECRET_KEY!,
  apiVersion: 'v2',
});
// No token code. It fetches one on the first send.

from sendgo import Sendgo

client = Sendgo(
    access_key=os.environ["SENDGO_ACCESS_KEY"],
    secret_key=os.environ["SENDGO_SECRET_KEY"],
    api_version="v2",
)

<?php

$sendgo = new Sendgo\Php\Sendgo([
    'access_key'  => $_ENV['SENDGO_ACCESS_KEY'],
    'secret_key'  => $_ENV['SENDGO_SECRET_KEY'],
    'api_version' => 'v2',
]);

client, err := sendgo.New(sendgo.Config{
    AccessKey:  os.Getenv("SENDGO_ACCESS_KEY"),
    SecretKey:  os.Getenv("SENDGO_SECRET_KEY"),
    ApiVersion: "v2",
})

Build the client once and reuse it. A new client per request throws away the cached token and fetches a new one every time. The Laravel, Spring and NestJS extensions register a singleton, so they avoid this by construction.

Authentication errors

Code	HTTP	Cause
INVALID_ACCESS_KEY	401	Key does not exist, or the secret is wrong
ACCESS_KEY_NOT_APPROVED	403	App is still pending approval
IP_NOT_ALLOWED	403	Called from outside the app's IP allowlist

IP_NOT_ALLOWED shows up constantly during local development. Leave the allowlist empty on a development app, or add your own IP. For production, check the actual outbound IP — behind a NAT gateway or load balancer it is not the instance IP.

Next

• Send your first Kakao Alimtalk in five minutes
• Error codes and retry strategy