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SMSLong-form SMSMMSSMPP / APIVoice OTPLookupRCS

International SMS Messaging
from Korea, Global delivery

Send OTP, notifications, alerts, and customer messages to 200+ countries through SureM's global SMS infrastructure, REST API, or SMPP integration.

Talk to Global Messaging Team → View API Integration
200+
Countries
800+
Carriers
REST / SMPP
Integration
26 yrs
Experience

Why SureM for international SMS?

Most international SMS providers route Korea-bound messages through third-party hubs — which Korean carriers deprioritize or filter. SureM operates direct contracts with SKT, KT, and LG U+, the only path for consistent Korean SMS delivery without third-party hub routing.

Direct Korean Carriers
Connected directly to SKT, KT, LG U+, the only path for reliable delivery.
No Third-party Hubs
No intermediary routes or reseller hops — better quality, higher deliverability.
High Delivery Success
Optimized routes and real-time monitoring deliver 97%+ success rate.
Unicode Support
Full Unicode support for Korean, Chinese, Japanese, Arabic, and more.
REST API
Developer-friendly REST API for seamless integration and real-time delivery.
SMPP Support
Enterprise-ready SMPP interface for high-volume messaging.

Who is this service for?

One integration for teams sending across borders.

Apps & platforms
OTP, login verification, account alerts.
E-commerce businesses
Order confirmations, shipping updates, delivery notifications.
Global enterprises
Customer notifications across multiple countries.
Marketing & CRM teams
Promotions, reminders, re-engagement campaigns.

Common use cases

Common use cases: OTP verification, order confirmations, appointment reminders, shipping alerts, account notifications, marketing campaigns

How to get started

01
Get credentials
Create a SureM account and receive your API credentials.
02
Connect via REST or SMPP
Send messages from your application or business system.
03
Send and monitor
Review delivery outcomes and monitor performance.

How message delivery works

Message delivery flow: Your system to SureM gateway to Destination carrier to Customer handset

International SMS strengths

200+ countries · 800+ carriers
SureM provides direct connectivity across 200+ countries and 800+ carriers for international delivery planning.
99.9% SLA
SureM operates with a 99.9% SLA together with around-the-clock monitoring for active messaging operations.
Multilingual sending
Send in Korean, English, Simplified and Traditional Chinese, Japanese, Hindi, Arabic, Thai, Indonesian, and other languages — with solutions for multilingual character-corruption issues.
Local-time scheduling
Schedule sends to arrive in the recipient's local time zone for reminders, campaigns, and operational traffic across regions.
24/7 monitoring with account manager
Every account receives a dedicated 1:1 account manager, real-time monitoring of success/failure/volume, and a weekly performance report with consulting.
A2P bulk sending
Application-to-phone workflows support address books, saved templates, scheduled send, and integration modules for client environments, while Korean direct-carrier handling is described as processing more than 10,000 messages per second for heavier traffic.

Ways to send

Choose the method that fits your business and technical needs.

01
02
03
API integration
For automated transactional and application messaging.
Real-time messaging
RESTful API
Easy integration
SMPP
For enterprise and high-volume messaging.
High throughput
Stable & reliable
Enterprise ready
Web portal
For non-developer bulk and campaign sending.
Easy to use
Upload & send
Track & manage

Country-specific compliance

Singapore
Messages without a registered local sender ID are automatically prefixed with “Likely Scam” by regulation — plan sender ID registration before launch.
China
Local sender ID (SID) and the exact message body must be pre-registered before bulk dispatch. Coordinate message templates with SureM in advance.
Vietnam
Messages must follow prescribed header and footer formats. Traffic that does not match the required format cannot be delivered.
Korea inbound
Korea’s top 3 carrier NPDB (Number Portability Database) is fully integrated. Messages route correctly to ported numbers and reach minor carriers, Ann Phone, internet-phone (070), and KT Powertel (013) numbers.
Need to send SMS into Korea?
SureM supports inbound messaging through direct carrier connectivity and NPDB integration.
Explore Korea SMS Provider →

How international SMS pricing works

Pricing can vary by destination country, carrier route, sender requirements, message encoding, commercial model, and traffic volume.

01
Destination country
Pricing varies by country.
02
Route type
Carrier routes impact delivery and cost.
03
Sender ID requirements
Rules and approval needs vary by market.
04
Message encoding
Encoding type affects message handling.
05
Commercial model
Pricing models depend on customer setup.
06
Traffic volume
Higher volumes often unlock better rates.

Sender ID & delivery reports

What is Sender ID?
Sender ID is the name or number recipients see as the message source. Some countries require it to be pre-registered before delivery.
Can I receive delivery reports?
Yes. Real-time delivery receipts (DLR) confirm whether each message reached the handset. They are available via API callback, SMPP, and the web portal.

Detailed policies are available in the API Docs or FAQ below.

Simple API request example

For developers integrating transactional messaging.

{
    "type": "SMS",
    "from": "SureM",
    "to": ["+819012345678"],
    "message": "Your verification code is 483920. Valid for 5 minutes."
}
View API documentation →

For developers integrating transactional messaging.

Frequently asked questions

What is the maximum character limit for international SMS?

Standard international SMS supports up to 160 characters using GSM-7 encoding (Latin alphabet). For Korean, Chinese, Japanese, Arabic, and other non-Latin scripts, UCS-2 encoding is used, which supports up to 70 characters per message. Messages exceeding these limits are automatically split into multiple segments and reassembled on the recipient's device as a single concatenated message (C-SMS).

Yes. SureM uses UCS-2 encoding to deliver Korean, Chinese, Japanese, Arabic, and 20+ other languages without character corruption. Character corruption — where text appears as garbled symbols — is a common issue with providers that use non-Unicode routing. SureM's UCS-2 pipeline ensures your message arrives exactly as written, regardless of destination country or carrier.

SureM operates direct carrier connections to South Korea's three major mobile operators — SKT, KT, and LG U+ — with no third-party hub routing. Most international SMS providers route Korea-bound messages through intermediary hubs, which Korean carriers deprioritize or filter as potential spam. SureM's direct interconnection supports throughput of 10,000+ messages per second and integrates Korea's NPDB (Number Portability Database) for accurate delivery to ported numbers.

Yes. SureM supports both outbound messaging (Korea to international, 200+ countries) and inbound messaging (international to Korea) through direct carrier connections to SKT, KT, and LG U+. Inbound SMS enables use cases such as two-way customer conversations, mobile number verification, and reply-based campaigns for international audiences communicating with Korean businesses.

Several countries enforce sender ID registration requirements that affect deliverability. Key examples include:

  • Singapore: Sender ID pre-registration via a local entity is mandatory. Unregistered sender IDs are automatically labeled [Likely-SCAM] by Singapore carriers.
  • China: Sender ID and message content must be pre-registered. Messages containing prohibited content categories (gambling, politics, adult content) are blocked automatically. An opt-out phrase (拒收请回复R) is required at the end of promotional messages.
  • Vietnam: Sender ID pre-registration is strongly recommended. Only pre-approved message templates are accepted for bulk delivery.

SureM provides country-specific compliance guidance and sender ID registration support as part of the onboarding process.

SMS (Short Message Service) supports up to 160 characters (GSM-7) or 70 characters (UCS-2) in a single message segment. C-SMS (Concatenated SMS) automatically combines multiple SMS segments into a single message for the recipient, supporting up to 500 characters — suitable for order confirmations, reservation details, and longer notifications. LMS (Long Message Service) is a Korea-specific message type supporting up to 2,000 bytes of text, used for domestic Korean messaging where extended content is required.

Related
SMS API ↗Long SMS (C-SMS) ↗MMS ↗SMPP ↗Voice OTP ↗Number Lookup ↗

Start sending
international SMS

Talk with SureM's messaging specialists.
We’ll help design the right workflow for your business.

Start sending international SMS → intlsales@surem.com
SureM is a Korea-based business messaging infrastructure provider with 26 years of experience.
SureM helps global messaging partners, foreign-invested companies in Korea, and Korean enterprises deliver SMS, LMS, MMS, RCS, Kakao, WhatsApp Business, Voice OTP,
and international messages through reliable local network connectivity and global messaging reach.