Technical Analysis and Recent Updates of Xi'an “One Code Pass” System

On January 4, users reported that the Xi'an “One Code Pass” service was unavailable due to overload; the city’s big‑data management bureau confirmed that traffic throttling was being applied and the service would be gradually reopened.

The technical support team received the “Xi'an Youth May Fourth Medal” for their pandemic‑response work, and the platform now hosts over 27.81 million registered users with daily visits in the tens of millions and cumulative trips exceeding 1.382 billion.

Two procurement notices are detailed: the March 2, 2020 single‑source purchase of the pandemic control platform development by China Telecom, and the December 10, 2020 single‑source purchase of a security platform (including AiLPHA big‑data analysis, traffic probes, database audit, bastion host, WAF, anti‑tamper, and EDR solutions) from Hangzhou Anheng Information Technology.

On December 30‑31, 2021, the Ministry of Industry and Information Technology’s chief engineer visited the Xi'an “One Code Pass” team, emphasizing political responsibility, network stability, security hardening, big‑data support, and operational safeguards.

Technical analysis from a Zhihu post identifies the main cause of repeated crashes: all static resources (JS/CSS/images) are served from a single exit without CDN, leading to an estimated peak load of 33 000 QPS, 500 KB per request, and roughly 125 Gbps outbound traffic, which overwhelms a single data‑center link.

The article concludes with a collection of interview questions and resources for readers interested in architecture, big‑data, and security topics.