Platform and reliability

SureM provides a 99.9% platform uptime SLA for enterprise customers, measured monthly. This SLA covers the availability of the messaging API and routing infrastructure. Separately, SureM maintains a 97%+ message delivery success rate — the ratio of messages confirmed delivered by the receiving carrier to total messages submitted, averaged across all active routes. These are two distinct metrics: the SLA measures platform availability, while the delivery rate measures end-to-end message success.

SureM uses network multiplexing with automatic fallback routing. Each destination has multiple carrier paths configured. When SureM sends a message, it selects the optimal path based on real-time route quality metrics — delivery rate, latency, and carrier status. If a primary route degrades or fails, traffic shifts automatically to the next best path without any action required from the customer. For domestic Korean sends, we route directly to SKT, KT, and LG U+ with no intermediate aggregators.

SureM supports REST API (HTTP/JSON) for all channel types including SMS, LMS, MMS, KakaoTalk Alimtalk & Friendtalk, RCS, Voice OTP, and international messaging. For high-volume carrier-grade sending, we operate SMPP v5 — SureM contributed to the development of the international SMPP standard. For MMS routing between carriers, we support MM4 (SMTP-based MMSC interconnect) and MM7 (WAP/OMA interface). Sample code is available for Java, Python, Node.js, PHP, and C#.

SureM's pre-send lookup and validation uses IMSI-based number lookup to check each recipient number before a message is dispatched. The lookup returns: country and carrier identification, handset availability status, number portability status (whether a number has been ported to a different carrier), and roaming status. This allows virtual numbers, inactive numbers, landlines, and unreachable numbers to be filtered out before the send — protecting your sender reputation and reducing wasted spend on undeliverable messages.

SureM's platform detects route degradation in real time through 24/7 traffic monitoring. When a primary carrier route fails or drops below quality thresholds, traffic is automatically shifted to the next available route — no manual intervention required. For KakaoTalk Alimtalk and Friendtalk, if a KakaoTalk delivery fails (e.g., recipient has notifications disabled), the platform automatically retries via SMS or LMS fallback. For RCS, failed delivers automatically fall back to SMS. Your account manager is notified of any significant routing events and will proactively communicate impact and resolution.

Yes. As an authorized KakaoTalk Biz Message official dealer (공식 딜러사), SureM provides full KakaoTalk business messaging infrastructure including Alimtalk (transactional template notifications), Friendtalk (promotional rich messages with images and buttons), and Brand Message. SureM handles channel setup, template submission and approval guidance, delivery routing, and automatic SMS/LMS fallback — all through the same REST API used for other channels. KakaoTalk reaches Korea's 47M+ monthly active users across all age groups.

Yes. SureM provides a test environment for API integration development. In the test environment you can submit send requests and receive simulated delivery results, test webhook/callback handling with mock DLR payloads, and verify request formatting, authentication, and error handling before going live — without incurring charges or sending messages to real recipients. Test credentials are issued during onboarding. Contact our technical support team to request sandbox access.