From 53f45cba2a1cdab01e407a3f4ca38bb898e8bcff Mon Sep 17 00:00:00 2001
From: Seungmin Nam <nhjbest22@g.skku.edu>
Date: Sat, 20 Jun 2026 21:57:43 +0000
Subject: [PATCH 1/3] feat(be): redirect to frontend after Kakao OAuth login

---
 .../apps/client/src/auth/auth.controller.ts   | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/apps/backend/apps/client/src/auth/auth.controller.ts b/apps/backend/apps/client/src/auth/auth.controller.ts
index 14cb376a19..2201f45e57 100644
--- a/apps/backend/apps/client/src/auth/auth.controller.ts
+++ b/apps/backend/apps/client/src/auth/auth.controller.ts
@@ -11,6 +11,7 @@ import {
   Param,
   ParseEnumPipe
 } from '@nestjs/common'
+import { ConfigService } from '@nestjs/config'
 import { AuthGuard } from '@nestjs/passport'
 import { Provider } from '@prisma/client'
 import { Request, Response } from 'express'
@@ -27,7 +28,10 @@ import type { GithubUser, KakaoUser } from './interface/social-user.interface'
 
 @Controller('auth')
 export class AuthController {
-  constructor(private readonly authService: AuthService) {}
+  constructor(
+    private readonly authService: AuthService,
+    private readonly configService: ConfigService
+  ) {}
 
   setJwtResponse = (res: Response, jwtTokens: JwtTokens) => {
     res.setHeader('authorization', `Bearer ${jwtTokens.accessToken}`)
@@ -158,15 +162,18 @@ export class AuthController {
   @AuthNotNeededIfPublic()
   @Get('kakao-callback')
   @UseGuards(AuthGuard('kakao'))
-  async kakaoLogin(
-    @Res({ passthrough: true }) res: Response,
-    @Req() req: Request
-  ) {
+  async kakaoLogin(@Res() res: Response, @Req() req: Request) {
     const kakaoUser = req.user as KakaoUser
     const result = await this.authService.kakaoLogin(kakaoUser)
+    const frontendUrl = this.configService.getOrThrow('FRONTEND_URL')
 
-    if ('oauthToken' in result) return result
+    if ('oauthToken' in result) {
+      return res.redirect(
+        `${frontendUrl}/login?modal=social-unlinked&oauthToken=${result.oauthToken}`
+      )
+    }
 
     this.setJwtResponse(res, result.jwtTokens)
+    return res.redirect(`${frontendUrl}/`)
   }
 }

From 6c36fe285aa07f5f16b8bf2c0a34c66bcdb30a65 Mon Sep 17 00:00:00 2001
From: Seungmin Nam <nhjbest22@g.skku.edu>
Date: Sat, 20 Jun 2026 21:59:27 +0000
Subject: [PATCH 2/3] feat(be): add FRONTEND_URL environment variable for local
 development

---
 .envrc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.envrc b/.envrc
index b0ae683268..77d8644766 100644
--- a/.envrc
+++ b/.envrc
@@ -1,3 +1,6 @@
+### Frontend ###
+export FRONTEND_URL="http://localhost:5525"
+
 ### MinIO ###
 export MINIO_ENDPOINT_URL="http://127.0.0.1:9000"
 export MEDIA_BUCKET_NAME="codedang-media"

From c3528c39e1090b4996e03e3e626613927f1c3a27 Mon Sep 17 00:00:00 2001
From: Seungmin Nam <nhjbest22@g.skku.edu>
Date: Sat, 20 Jun 2026 22:04:45 +0000
Subject: [PATCH 3/3] fix(be): import ConfigService in AuthController tests

---
 apps/backend/apps/client/src/auth/auth.controller.spec.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/apps/backend/apps/client/src/auth/auth.controller.spec.ts b/apps/backend/apps/client/src/auth/auth.controller.spec.ts
index eb86acb805..b6d6f80ba1 100644
--- a/apps/backend/apps/client/src/auth/auth.controller.spec.ts
+++ b/apps/backend/apps/client/src/auth/auth.controller.spec.ts
@@ -1,6 +1,6 @@
+import { ConfigService } from '@nestjs/config'
 import { Test, type TestingModule } from '@nestjs/testing'
 import { expect } from 'chai'
-import { UserService } from '@client/user/user.service'
 import { AuthController } from './auth.controller'
 import { AuthService } from './auth.service'
 
@@ -12,7 +12,7 @@ describe('AuthController', () => {
       controllers: [AuthController],
       providers: [
         { provide: AuthService, useValue: {} },
-        { provide: UserService, useValue: {} }
+        { provide: ConfigService, useValue: {} }
       ]
     }).compile()
     controller = module.get<AuthController>(AuthController)