https://www.youngju.dev/blog 천천히 올바르게. AI Researcher & DevOps Engineer Youngju's tech blog. GPU/CUDA, LLM, MLOps, Kubernetes AI workloads, distributed training, and data engineering. ko fjvbn2003@gmail.com (Youngju Kim) fjvbn2003@gmail.com (Youngju Kim) Sat, 16 May 2026 00:00:00 GMT https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive.en https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive.en In 2026 the build-vs-buy line for web app auth is sharper than ever. From libraries like Auth.js v5, Lucia v3, and better-auth to managed SaaS like Clerk, Stytch, WorkOS, Kinde, SuperTokens, and Frontegg — this deep dive covers OAuth flows, passkeys, magic links, OTP, TOTP, sessions vs JWT, B2B SSO/SCIM, OWASP A07, and Korean (NAVER/Kakao) / Japanese (LINE/Yahoo!JP) local ID providers. Which team should pick what, with migration scenarios and 30+ real references. Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) englishauth-librariesauth-jsluciabetter-authclerkstytchworkoskindesupertokensfronteggoauthpasskeyswebauthn2026deep-dive https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive.ja https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive.ja 2026年、ウェブアプリ認証における「作るか、買うか」の境界はかつてないほど鮮明になった。Auth.js v5、Lucia v3、better-auth といったライブラリから、Clerk、Stytch、WorkOS、Kinde、SuperTokens、Frontegg のようなマネージド SaaS まで — OAuth フロー、パスキー、マジックリンク、OTP、TOTP、セッション vs JWT、B2B SSO/SCIM、OWASP A07、韓国(NAVER/Kakao) と日本(LINE/Yahoo!JP) のローカル ID プロバイダまで、まとめて整理する。どのチームに何を選ぶべきか、移行シナリオと 30+ の本物のリファレンスとともに語る。 Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) 日本語auth-librariesauth-jsluciabetter-authclerkstytchworkoskindesupertokensfronteggoauthpasskeyswebauthn2026deep-dive https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive https://www.youngju.dev/blog/culture/2026-05-16-api-web-auth-libraries-2026-authjs-v5-lucia-better-auth-clerk-stytch-workos-kinde-supertokens-frontegg-deep-dive 2026년 웹앱 인증은 "직접 만든다 vs 산다"의 갈림길이 더 선명해졌다. Auth.js v5, Lucia v3, better-auth 같은 라이브러리부터 Clerk, Stytch, WorkOS, Kinde, SuperTokens, Frontegg 같은 매니지드 SaaS까지 — OAuth 흐름, 패스키, 매직 링크, OTP, TOTP, 세션 vs JWT, B2B SSO/SCIM, OWASP A07, 한국(NAVER·Kakao) / 일본(LINE·Yahoo!JP) 로컬 ID 제공자까지 한 번에 정리한다. 어떤 팀이 무엇을 골라야 할지, 실전 마이그레이션과 함정까지 30+ 출처와 함께 풀어낸다. Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) auth-librariesauth-jsluciabetter-authclerkstytchworkoskindesupertokensfronteggoauthpasskeyswebauthn2026deep-dive