OpenAPI Specification

The machine-readable contract for the Sendgo API

If your language has no official Sendgo SDK — or you want to generate your own client — start from the OpenAPI 3.0.3 spec.

• Always current: https://sendgo.io/openapi.yaml
• Source: send-go/openapi
• Server: https://api.sendgo.io/api

---

Endpoints

Channel	Method	Path
Issue token	POST	/{version}/token
Kakao Alimtalk	POST	/{version}/notices/send
Kakao Friendtalk — Deprecated	POST	/{version}/friends/send
Brand Message — send	POST	/{version}/brand-messages/send
Brand Message — list campaigns	GET	/{version}/brand-messages
Brand Message — campaign detail	GET	/{version}/brand-messages/{campaign_id}
SMS / LMS / MMS	POST	/{version}/messages/send
Short URL — create	POST	/{version}/short-urls
Short URL — list	GET	/{version}/short-urls
Short URL — detail	GET	/{version}/short-urls/{code}
Short URL — reaction stats	GET	/{version}/short-urls/{code}/stats
Short URL — stop redirecting	DELETE	/{version}/short-urls/{code}

{version} is v1 or v2. Brand Message is v2 only.

Friendtalk was discontinued on 2025-12-31 under Kakao's policy. Since 2026-01-01 requests to /{version}/friends/send are delivered as Brand Message (free-form) automatically — the call still succeeds, but what goes out is a Brand Message. The endpoint is not being removed: it is still the only path for free-form types (FT/FI/FW) to individual recipients, and /{version}/brand-messages/send returns NOT_A_BRAND_MESSAGE for that combination. Use Brand Message for template-based rich types (FL/FC/FM/FP/FA), non-friend targeting (N/I) and broadcasts (F).

---

Authentication

Two steps.

1. Issue a token with Basic auth over accessKey:secretKey:

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

2. Call the API with that token as a Bearer credential:

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

v1 expects the token Base64-encoded a second time; v2 sends it verbatim. Getting this backwards is the usual cause of a 401 on a token you just issued.

Tokens are valid for 24 hours. Read expiresAt (v2) / expires_at (v1) from the issue response, cache the token, and reissue only when it is about to lapse — issuing one per request is wasted latency on every single call.

Requests are also checked against the IP allow-list configured for the application, so a token alone is not enough from an unregistered address (IP_NOT_ALLOWED).

---

Send an Alimtalk

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

---

Send a Brand Message

# Targeted — targeting M/N/I requires `contacts`
curl -X POST https://api.sendgo.io/api/v2/brand-messages/send \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "targeting": "M",
    "messageType": "FL",
    "friendTemplateUuid": "9cd5460b-6458-4edc-9b11-c26d3013c340",
    "contacts": [{ "contact": "01012345678", "var1": "29,000 KRW" }]
  }'

# Broadcast — every consenting channel friend, no recipient list
curl -X POST https://api.sendgo.io/api/v2/brand-messages/send \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "targeting": "F",
    "messageType": "FW",
    "friendTemplateUuid": "9cd5460b-6458-4edc-9b11-c26d3013c340"
  }'

A broadcast is processed asynchronously upstream, so the send response only acknowledges acceptance. Poll the campaign for progress:

curl "https://api.sendgo.io/api/v2/brand-messages/$CAMPAIGN_ID" \
  -H "Authorization: Bearer $TOKEN"

GET /{version}/brand-messages returns Brand Message campaigns only (BRAND_GROUP, BRAND_BASIC) — use /{version}/friends for Friendtalk campaigns.

---

Response envelope

Success:

{
  "traceId": "01J2X8N4YV5T3Q9M0K7B6C5D4E",
  "message": "Success",
  "data": { }
}

Failure:

{
  "traceId": "01J2X8N4YV5T3Q9M0K7B6C5D4E",
  "code": "INVALID_TEMPLATE_CODE",
  "message": "The template code does not exist.",
  "errors": { },
  "timestamp": "2026-08-10 04:31:22"
}

Both shapes are flat — the error fields are not nested under data or error. Branch on code, not on message: messages are prose and may be reworded, codes are the contract. Include traceId when you contact support; it identifies the exact request in our logs.

timestamp is server-local (Y-m-d H:i:s, Asia/Seoul) with no offset — parse it as KST rather than as UTC or ISO 8601.

---

Generate a client

# TypeScript
npx @openapitools/openapi-generator-cli generate \
  -i https://sendgo.io/openapi.yaml -g typescript-fetch -o ./sendgo-client

# Python
openapi-generator-cli generate \
  -i https://sendgo.io/openapi.yaml -g python -o ./sendgo-client

# Go
openapi-generator-cli generate \
  -i https://sendgo.io/openapi.yaml -g go -o ./sendgo-client

Prefer the official SDK where one exists. A generated client gives you typed request bodies, but nothing else: the SDKs cache the token, reissue it transparently on TOKEN_EXPIRED / TOKEN_MISMATCH, and retry that one request — logic you would otherwise write yourself in every service. See the SDK index for the 20 supported languages and frameworks.

---

Explore and validate

Paste openapi.yaml into Swagger Editor to browse the endpoints and schemas visually.

npx @redocly/cli lint openapi.yaml

---

For AI coding tools

The spec is one of several machine-readable entry points:

URL	Contents
/openapi.yaml	This specification
/llms.txt	Index of every guide, in the llmstxt.org format
/llms-full.txt	Every guide concatenated as plain text
/{lang}/sdk/{slug}.md	The raw markdown of any SDK guide

---

Package information

• Package: send-go/openapi (GitHub)
• Repository: send-go/openapi
• License: MIT

Getting your API keys

Sign in to Sendgo and open API/SDK → API integration to issue an access key and secret key. Register a Kakao sender profile under Kakao channel for Alimtalk and Brand Message, and a caller ID under Sender numbers for SMS.