Business Messaging Services for Korea and Global Markets
SureM provides business messaging services for enterprises, platforms, and global partners that need reliable message delivery in Korea and abroad. Our services include SMS, LMS, MMS, RCS, Kakao/WhatsApp messaging, Voice OTP, SMPP connectivity, and international messaging — delivered across 200+ countries with a 97%+ success rate. From bulk SMS for marketing to OTP authentication and rich interactive flows, we handle routing, delivery, and operations end-to-end.
SMS
The reliable standard for business messaging
Send instant, dependable text messages to customers anywhere — order alerts, one-time passwords (OTP), two-factor authentication (2FA) codes, appointment reminders, shipping notifications, and promotional SMS campaigns.
With direct carrier connections in Korea and 200+ countries and a 97%+ delivery success rate, SureM makes sure your most important messages always arrive. Our SMS gateway supports high-volume bulk SMS sending, real-time delivery receipts (DLR), sender ID customization, and Unicode messaging for Korean and international character sets. Businesses in e-commerce, finance, healthcare, and logistics rely on SureM's SMS API for mission-critical notification delivery.
QWhat is a business SMS service?
A business SMS service, also called enterprise SMS or SMS gateway, lets companies send automated text messages to customers at scale — including OTP codes, order confirmations, appointment reminders, and marketing campaigns — through an API or web platform.
QWhat is the SMS open rate?
SMS has a 98% open rate, significantly higher than email, and most messages are read within minutes of delivery — making it a high-attention channel for time-sensitive business communications.
QDoes SureM support SMS API integration?
Yes. SureM provides REST-based SMS API integration for sending messages, receiving delivery reports, and connecting business messaging into applications, CRM platforms, and e-commerce systems.
How it works
No garbled text, anywhere in the world
Sending across borders often breaks non-Latin characters. SureM delivers your message in full Unicode — Korean, Chinese, Japanese, Arabic and more arrive exactly as written, with no corruption or dropped characters on the recipient's handset.
C-SMS
(Concatenated SMS)Long messages, delivered as one
C-SMS (Concatenated SMS) automatically splits long text into multiple parts and reassembles them seamlessly on the recipient's phone — so you can send messages beyond the standard 160-character SMS limit without losing readability.
Standard SMS is capped at 160 characters (or 70 characters for Unicode/Korean text). C-SMS, also known as long SMS or multipart SMS, removes this constraint by chaining message segments transparently — the recipient sees one continuous message, regardless of length. This is especially valuable for sending detailed order summaries, compliance disclosures, multilingual notifications, and customer service responses.
With automatic overseas long-message processing and auto-routing across 200+ countries, SureM delivers your full message clearly, in any supported language. Our platform handles segment concatenation, international encoding, and carrier-level routing automatically — no additional configuration required on your end.
What is concatenated SMS?
Concatenated SMS, also called long SMS or multipart SMS, splits a long text into several SMS segments and reassembles them on the recipient phone so the user sees one continuous message.
How many characters can a C-SMS message contain?
The exact number depends on language encoding and carrier rules, but C-SMS is designed for long messages beyond the standard SMS limit, with automatic segmentation and reassembly. The supplied service content shows a long-message capacity example of about 2,000 bytes.
KakaoTalk
(Alimtalk & Friendtalk)Reach Korean customers where they already are
Connect through KakaoTalk, Korea's most-used messaging app with over 47 million monthly active users in South Korea — covering 93% of the Korean smartphone population, with business messages your customers actually open.
Send template-based Alimtalk notifications (orders, bookings, alerts) and Friendtalk (formerly Chingutalk) promotional messages — with automatic SMS fallback so no message is ever missed. Alimtalk is Korea's primary channel for transactional business notifications, while Friendtalk supports rich promotional content including images, buttons, and coupon links. Both channels require a verified KakaoTalk Business channel, which SureM helps you establish.
SureM guides you through channel setup, template approval, and delivery. With SureM's KakaoTalk Biz Message API, businesses can automate Alimtalk sends, track delivery and read status, and configure SMS fallback for recipients who disable KakaoTalk notifications — ensuring zero message loss across all customer segments.
QWhat is KakaoTalk Alimtalk?
Alimtalk is a KakaoTalk business notification message used for transactional and informational content such as order confirmations, reservation notices, delivery updates, payment notices, and account alerts. Messages are sent through approved templates.
QWhat is the difference between Alimtalk and Friendtalk?
Alimtalk is used for transactional notifications based on approved templates. Friendtalk is used for promotional messages, marketing campaigns, coupons, and richer customer engagement through a KakaoTalk Business channel.
QDoes KakaoTalk Alimtalk have SMS fallback?
Yes. SureM can automatically retry failed or unavailable KakaoTalk notifications through SMS or LMS so important customer messages are still delivered.
RCS
(Rich Communication Services)The next generation of business messaging
RCS brings branded, interactive, app-like experiences right into your customer's default messaging inbox — with your logo, verified sender name, images, buttons, and carousels. Unlike SMS, RCS messages display your brand identity with a verified business profile, giving customers confidence that the message is authentic and reducing the risk of phishing and SMS fraud.
Richer than SMS and more trusted, RCS helps your business stand out while keeping the simple reach of a text message. RCS Business Messaging (RBM) supports suggested replies, quick-action buttons, product carousels, image galleries, and read receipts — transforming the native messaging inbox into a fully branded customer engagement channel. In South Korea, RCS is supported by all three major carriers (SKT, KT, LG U+) on both Android and iOS (since September 2024), with SureM providing direct carrier-grade RCS delivery.
For maximum reach, SureM automatically falls back to SMS when RCS is unavailable on a recipient's device or carrier — so you get rich messaging where it's supported and reliable SMS delivery everywhere else. No extra integration required.
QWhat is RCS messaging?
RCS is a next-generation business messaging format that brings verified sender identity, rich media, buttons, carousels, suggested replies, and read receipts into the default mobile messaging inbox.
QHow is RCS different from SMS?
SMS is text-only and universally supported. RCS adds verified business branding, richer layouts, interactive buttons, images, carousels, and read receipts while keeping the native messaging experience where supported.
QIs RCS supported in South Korea?
Yes. RCS is supported by all three major Korean carriers, SKT, KT, and LG U+, and the supplied service content notes support on both Android and iOS since September 2024.
QWhat happens if a recipient's phone doesn't support RCS?
SureM can automatically fall back to SMS when RCS is unavailable on a recipient's device or carrier, so the message still reaches the customer through a reliable channel.
How Voice Works
Hi Linda! Your order
# A421 has shipped 🚚
Reply STOP to opt out
9:32 AM ✓✓
WhatsApp Business
(Cloud API)
Reach global customers on the world’s most-used messaging app
Connect with customers on WhatsApp Business, used by 2.5 billion people across 180+ countries — the leading messaging channel in Latin America, Europe, the Middle East, India, and Southeast Asia. SureM provides WhatsApp Business API delivery as part of one unified messaging platform alongside SMS, RCS, and KakaoTalk.
Send pre-approved template messages for notifications, OTPs, and customer service conversations — with rich media (images, documents, video), interactive buttons, quick replies, and list selections. WhatsApp's verified Business Profile and end-to-end encryption give your brand the trust and authenticity needed for high-engagement customer communication globally.
SureM handles WhatsApp Business Account verification, template approval submissions, and ongoing campaign delivery. Combined with SureM's Korea-strong SMS, Kakao, and RCS coverage, you get a single integration that reaches customers wherever they are — in Korea or abroad — through their preferred messaging channel.
QWhat is WhatsApp Business API?
WhatsApp Business API lets companies send approved notifications, service messages, and customer conversations through WhatsApp at scale.
QHow do WhatsApp message templates get approved?
Templates are submitted for review before use. SureM helps prepare, submit, and operate approved message templates for business use cases.
QWhat are common WhatsApp Business use cases?
Common use cases include order updates, OTP delivery, appointment reminders, support conversations, rich media notifications, and global customer engagement.
QIs WhatsApp Business available in Korea?
Yes. SureM can combine WhatsApp Business with SMS, KakaoTalk, and RCS so Korean and global customers receive messages through the right channel.
Compare at a glance
Find the right channel for your message.
| Feature | SMS | LMS (C-SMS) | Kakao | RCS | |
|---|---|---|---|---|---|
| Message length | ~90 bytes | ~2,000 bytes | Long + template | Long + rich | Long + template |
| Subject line | - | Yes | - | - | Header optional |
| Images / media | - | - | Yes | Yes | Yes |
| Buttons / interactive | - | - | Yes | Yes | Yes |
| Verified brand sender | - | - | Yes | Yes | Yes |
| Delivery | Any handset | Any handset | KakaoTalk app | Native messaging app | WhatsApp app |
| Primary region | Global | Korea-focused | Korea | Korea + global | Global (180+ countries) |
| Typical use | OTP, alerts | Detailed notices | Alerts & marketing | Branded campaigns | Global notifications |
Not sure which channel fits your message?
Tell us about your use case and we'll recommend the right mix of SMS, KakaoTalk, RCS, and WhatsApp — across Korea and 200+ countries.