Susi Server Outage

A recurring phenomenon in which university admissions systems are paralyzed by simultaneous access overload during the early admissions (Susi) application period.

Susi Server Outage

Overview

Susi Server Outage (수시 먹통) is a neologism referring to the phenomenon in which integrated application systems such as Jinhak Apply (진학어플라이) and Uway Apply (유웨이어플라이), along with individual universities' own application servers, are paralyzed by simultaneous access overload during the early admissions (Susi) application period, which takes place around September each year. As hundreds of thousands of applicants crowd into a narrow window within a fixed period, servers go down or payment and submission are delayed, and the anxiety of applicants and their parents is pointed to as a structural problem that repeats every year.

Main Content

Background

South Korean university admissions are broadly divided into early admissions (Susi), which select students without CSAT scores based on school records, essay exams, interviews, practical skills, and the like, and regular admissions (Jeongsi), which center on CSAT scores. Susi accounts for a large share—roughly 70–80% of total seats—and since most applicants can apply to up to six universities, application traffic is far more concentrated than for Jeongsi. The problem is that applications depend on a small number of platforms such as Jinhak Apply and Uway Apply, as well as the in-house systems of certain universities.

Causes

Concentration near the deadline: Most applicants rush to connect in the hours just before the deadline.
Limited server capacity: The infrastructure is insufficient to handle the number of concurrent users.
Multi-application structure: A single student applying to several universities generates duplicate session and payment requests.
Identity verification and payment integration: Overload cascades to authentication agencies and PG (payment gateway) servers.
Rush at specific times: Traffic surges at particular times, such as 10 a.m. and just before midnight.

Major Platforms

| Platform | Operator | Characteristics |

|---|---|---|

| Jinhak Apply | Jinhak | Integrated applications for multiple universities |

| Uway Apply | Uway | Integrated applications for multiple universities |

| University in-house systems | Individual universities | Built independently by major universities |

Major Cases

Susi server outages have occurred like an annual event, repeating virtually every year since the mid-2010s. In particular, as connections surged around midnight on the deadline day, complaints poured in saying "the server crashed," "I can't log in," and "I can't make a payment." Some universities took temporary measures such as extending the deadline or granting an additional application period.

Impact and Responses

Applicant anxiety: Fear that one may fail to submit an application in time grows, and cases of staying up all night the day before the deadline abound.
Extension of application hours: Universities and platforms extend deadlines or encourage staggered applications.
Server expansion: Platform operators expand servers every year and shift to cloud-based systems.
Intervention by education authorities: The Ministry of Education and the Korean Council for University Education have at times demanded measures to stabilize the application system.

Latest Trends

In 2024–2025 as well, cases of connection delays continued, centering on the first day and the deadline of Susi applications. Platform operators have introduced cloud autoscaling, queue systems (virtual waiting rooms), and encouragement of staggered applications, but overload still occurs at certain times just before the deadline. Recently, the share of mobile connections has surged, and Jinhak and Uway have introduced AI-based traffic prediction, reflecting a trend toward more sophisticated responses. However, many point out that applicants still prefer to connect just before the deadline, so the fundamental concentration has not been resolved. Some have proposed distributing the application period or introducing a lottery or advance reservation system.