> **The official Dart SDK for sending Kakao Alimtalk, Brand Message and SMS from a Dart server** `sendgo_flutter` is the official Dart SDK for the [Sendgo](https://sendgo.io) messaging API. > **Server-side only.** Never put your access key and secret key in a Flutter app — anything shipped to a device can be extracted from the bundle. Use this SDK from a Dart backend (Shelf, Serverpod, Dart Frog), Cloud Functions, or your own API, and have the app call *your* endpoint instead. Requires Dart 3.3 or newer. --- ## Install ```bash dart pub add sendgo_flutter ``` ```yaml # pubspec.yaml dependencies: sendgo_flutter: ^1.0.2 ``` --- ## Quick start ```dart import 'dart:io'; import 'package:sendgo_flutter/sendgo_flutter.dart'; final client = SendgoClient( accessKey: Platform.environment['SENDGO_ACCESS_KEY']!, secretKey: Platform.environment['SENDGO_SECRET_KEY']!, kakaoSenderKey: Platform.environment['SENDGO_KAKAO_SENDER_KEY'], smsSenderKey: Platform.environment['SENDGO_SMS_SENDER_KEY'], apiVersion: 'v2', ); // Send an Alimtalk await client.alimtalk.send(AlimtalkRequest( templateCode: 'ORDER_CONFIRM_001', contacts: [ Contact(contact: '01012345678', name: 'Gildong Hong', var1: 'ORD-001'), ], )); ``` Each channel is a field on the client: `alimtalk`, `friendtalk`, `brandMessage`, `sms`. Tokens are issued and refreshed inside the SDK. --- ## Alimtalk in detail ```dart // Multiple recipients await client.alimtalk.send(AlimtalkRequest( templateCode: 'ORDER_CONFIRM_001', contacts: [ Contact(contact: '01011111111', name: 'Gildong Hong', var1: 'ORD-001'), Contact(contact: '01022222222', name: 'Chulsoo Kim', var1: 'ORD-002'), ], )); // Scheduled send await client.alimtalk.send(AlimtalkRequest( templateCode: 'PROMO_SUMMER_2026', scheduleType: 'SCHEDULED', at: '2026-07-28 09:00:00', contacts: [Contact(contact: '01012345678', var1: 'Summer sale')], )); // Fall back to SMS when the Alimtalk fails await client.alimtalk.send(AlimtalkRequest( templateCode: 'DELIVERY_START_001', replaceSms: 'Y', smsSubject: '[Shipping notice]', smsContent: 'Your order has shipped.', contacts: [Contact(contact: '01012345678', var1: 'ORD-001')], )); ``` For named template variables beyond `var1`–`var8`, `Contact` also takes a map: ```dart Contact(contact: '01012345678', variables: {'title': 'Order', 'date': '2026-08-10'}); ``` `Contact.toJson()` merges `variables` into the payload, so named and numbered variables can be mixed. --- ## Friendtalk > ⚠️ **Deprecated — Friendtalk was discontinued on 2025-12-31 under Kakao's policy.** > Since 2026-01-01, Friendtalk send requests are automatically delivered as > **Brand Message (free-form)** by Kakao. Calls still succeed, and this is still the > only path for free-form types (`FT`/`FI`/`FW`) sent to individual recipients, so > there is no need to change working code right now. > > Use **Brand Message** instead for: > - template-based rich types (`FL`/`FC`/`FM`/`FP`/`FA`) > - recipients who are **not** channel friends (`targeting` = `N` / `I`) > - broadcasts to every opted-in channel friend (`targeting` = `F`) > > Message types map one-to-one and the server does the conversion — `FT`→`BT`, > `FI`→`BI`, `FW`→`BW`, `FL`→`BL`, `FC`→`BC`, `FM`→`BM`, `FP`→`BP`, `FA`→`BA`. ```dart await client.friendtalk.send(FriendtalkRequest( messageType: 'FI', content: "This week's featured products.", imageUrl: 'https://cdn.example.com/banner.jpg', imageLink: 'https://example.com/event', contacts: [Contact(contact: '01012345678')], )); ``` --- ## Brand Message Brand Message is the successor channel to Friendtalk. Message types map one-to-one (`FT`→`BT`, `FI`→`BI`, `FW`→`BW`, `FL`→`BL`, `FC`→`BC`, `FM`→`BM`, `FP`→`BP`, `FA`→`BA`); pass the **Friendtalk code** and the server converts it. Unlike Friendtalk it can also reach recipients who are **not channel friends** (`targeting: 'N'`) and **broadcast to every consenting channel friend** (`targeting: 'F'`). > v2 only. Set `apiVersion: 'v2'`. ```dart // Single send — channel friends await client.brandMessage.send(BrandMessageRequest( targeting: 'M', messageType: 'FL', friendTemplateUuid: '9cd5460b-6458-4edc-9b11-c26d3013c340', contacts: [Contact(contact: '01012345678', var1: '29,000 KRW')], )); // Broadcast — every consenting channel friend (no contacts) await client.brandMessage.broadcast(BrandMessageRequest( messageType: 'FW', friendTemplateUuid: '9cd5460b-6458-4edc-9b11-c26d3013c340', )); // Campaign lookups final list = await client.brandMessage.campaigns(count: 10); final one = await client.brandMessage.campaign('1f0a6d0e-6b3b-4f0f-9b2f-2f6f6a1b7c11'); ``` `broadcast()` calls `request.asBroadcast()`, which returns a copy with `targeting: 'F'` and no contacts. `toJson()` then omits the `contacts` key entirely rather than sending an empty list, which the API would reject. --- ## SMS / LMS / MMS ```dart // SMS (up to 90 bytes) await client.sms.sendSms(SmsRequest( content: '[Sendgo] Your code is 123456 (valid for 5 minutes)', contacts: [Contact(contact: '01012345678')], )); // LMS (long text, up to 2,000 bytes) await client.sms.sendLms(SmsRequest( subject: '[Important] Scheduled maintenance', content: 'Maintenance: 2026-07-25 02:00–06:00', contacts: [Contact(contact: '01012345678')], )); // MMS await client.sms.sendMms(SmsRequest( subject: '[Event] July deals', content: "Check out this month's deals!", contacts: [Contact(contact: '01012345678')], )); ``` --- ## Using it from a Flutter app safely The app must not hold Sendgo keys. Put the SDK behind your own endpoint and call that: ```dart // server/bin/server.dart — Shelf import 'package:shelf/shelf.dart'; import 'package:shelf_router/shelf_router.dart'; import 'package:sendgo_flutter/sendgo_flutter.dart'; final client = SendgoClient( accessKey: Platform.environment['SENDGO_ACCESS_KEY']!, secretKey: Platform.environment['SENDGO_SECRET_KEY']!, kakaoSenderKey: Platform.environment['SENDGO_KAKAO_SENDER_KEY'], apiVersion: 'v2', ); final router = Router() ..post('/notify', (Request request) async { final body = jsonDecode(await request.readAsString()) as Map; await client.alimtalk.send(AlimtalkRequest( templateCode: 'ORDER_CONFIRM_001', contacts: [Contact(contact: body['phone'] as String, var1: body['orderNo'] as String)], )); return Response.ok('{"ok":true}'); }); ``` The Flutter app then calls `POST /notify` on your server, authenticated with your own session — the Sendgo keys never leave the backend. --- ## Error handling ```dart try { await client.alimtalk.send(request); } on SendgoException catch (e) { switch (e.errorCode) { case 'INVALID_ACCESS_KEY': case 'INVALID_SECRET_KEY': log.severe('Check the Sendgo API keys'); case 'PAYMENT_REQUIRED': log.severe('Out of Sendgo credit'); case 'IP_NOT_ALLOWED': log.severe('IP is not allow-listed'); case 'INVALID_TEMPLATE_CODE': log.warning('Unknown template'); default: if (e.statusCode >= 500) { await retryLater(request); // transient } else { log.severe('Sendgo ${e.statusCode}: ${e.message}'); } } } ``` Branch on `errorCode`, not on the message text — messages can change, codes are the contract. `TOKEN_EXPIRED` and `TOKEN_MISMATCH` are handled inside the SDK: the token is reissued and the request retried once. --- ## Configuration options | Parameter | Type | Required | Default | Description | |-----------|------|----------|---------|-------------| | `accessKey` | `String` | **required** | — | Sendgo access key | | `secretKey` | `String` | **required** | — | Sendgo secret key | | `kakaoSenderKey` | `String?` | optional | `null` | Kakao sender profile key | | `smsSenderKey` | `String?` | optional | `null` | SMS caller ID key | | `apiVersion` | `String` | optional | `'v1'` | API version (`v1` \| `v2`) | | `baseUrl` | `String` | optional | `'https://sendgo.io'` | API base URL | --- ## Short URL Short URLs shrink the links in your message body and count whether they were actually clicked. SMS is billed by byte, so a shorter link leaves more room for copy. > v2 only. Shortening the same target URL again **returns the existing link**. Pass `forceNew` to mint a new code when you want per-campaign reaction figures kept separate. `deactivate` does not delete the link — it only stops the redirect. Use it when a link in an already-sent message has to be killed; the accumulated stats stay, and visitors to a stopped link get `410 Gone`. ```dart final created = await sendgo.shortUrl.create(const ShortUrlRequest( targetUrl: 'https://example.com/promotions/summer-sale', title: 'Summer sale landing', )); final code = created['data']['code'] as String; final link = created['data']['shortUrl'] as String; // Reaction stats — daily series + device / referrer / country breakdowns final stats = await sendgo.shortUrl.stats(code, from: '2026-08-01'); await sendgo.shortUrl.list(count: 10); await sendgo.shortUrl.show(code); await sendgo.shortUrl.deactivate(code); // Stops the redirect only; the stats stay ``` `stats` returns a daily series (`daily`) plus breakdowns by device (`byDevice`), referrer (`byReferer`) and country (`byCountry`). The daily series is read from a pre-aggregated table, so response time stays flat no matter how many clicks accumulate. --- ## Package information - **Package**: `sendgo_flutter` (pub.dev) - **Repository**: [send-go/flutter](https://github.com/send-go/flutter) - **Registry**: https://pub.dev/packages/sendgo_flutter - **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** to get your `kakaoSenderKey`, and a caller ID under **Sender numbers** for SMS.