cdnjs is a free distributed JS library delivery service.
Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Kakao platform provides various services such as Kakao Talk, Kakao Talk Channel, Kakao Story as well as Kakao Pay, Kakao Commerce, Kakao Page provided by the subsidiaries. Users can use all Kakao platform services with a united account called Kakao Account.
Naver Analytics is a Korean based analytics service.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.