diff --git a/build.gradle.kts b/build.gradle.kts
index 91ca0a6a..8cc4ad0e 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -59,7 +59,7 @@ kotlin {
 }
 
 sourceSets.main {
-    java.srcDirs("build/generated/ksp/main/kotlin")
+    kotlin.srcDirs("$buildDir/generated/ksp/main")
 }
 
 dependencies {
diff --git a/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/PostResponse.kt b/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/PostResponse.kt
index c6845da9..8aee3f68 100644
--- a/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/PostResponse.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/PostResponse.kt
@@ -5,7 +5,7 @@ import dev.usbharu.hideout.domain.model.hideout.entity.User
 import dev.usbharu.hideout.domain.model.hideout.entity.Visibility
 
 data class PostResponse(
-    val id: Long,
+    val id: String,
     val user: UserResponse,
     val overview: String? = null,
     val text: String? = null,
@@ -17,7 +17,7 @@ data class PostResponse(
     companion object {
         fun from(post: Post, user: User): PostResponse {
             return PostResponse(
-                id = post.id,
+                id = post.id.toString(),
                 user = UserResponse.from(user),
                 overview = post.overview,
                 text = post.text,
diff --git a/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/UserResponse.kt b/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/UserResponse.kt
index ab8c1829..6213a7e4 100644
--- a/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/UserResponse.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/domain/model/hideout/dto/UserResponse.kt
@@ -3,7 +3,7 @@ package dev.usbharu.hideout.domain.model.hideout.dto
 import dev.usbharu.hideout.domain.model.hideout.entity.User
 
 data class UserResponse(
-    val id: Long,
+    val id: String,
     val name: String,
     val domain: String,
     val screenName: String,
@@ -14,7 +14,7 @@ data class UserResponse(
     companion object {
         fun from(user: User): UserResponse {
             return UserResponse(
-                id = user.id,
+                id = user.id.toString(),
                 name = user.name,
                 domain = user.domain,
                 screenName = user.screenName,
diff --git a/src/main/kotlin/dev/usbharu/hideout/plugins/Routing.kt b/src/main/kotlin/dev/usbharu/hideout/plugins/Routing.kt
index 8d4942f2..711d9c9a 100644
--- a/src/main/kotlin/dev/usbharu/hideout/plugins/Routing.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/plugins/Routing.kt
@@ -13,9 +13,9 @@ import dev.usbharu.hideout.service.activitypub.ActivityPubUserService
 import dev.usbharu.hideout.service.api.IPostApiService
 import dev.usbharu.hideout.service.api.IUserApiService
 import dev.usbharu.hideout.service.auth.HttpSignatureVerifyService
-import dev.usbharu.hideout.service.reaction.IReactionService
 import dev.usbharu.hideout.service.auth.IJwtService
 import dev.usbharu.hideout.service.core.IMetaService
+import dev.usbharu.hideout.service.reaction.IReactionService
 import dev.usbharu.hideout.service.user.IUserAuthService
 import dev.usbharu.hideout.service.user.IUserService
 import io.ktor.server.application.*
diff --git a/src/main/kotlin/dev/usbharu/hideout/routing/api/internal/v1/Users.kt b/src/main/kotlin/dev/usbharu/hideout/routing/api/internal/v1/Users.kt
index 24a45006..5a90ea7b 100644
--- a/src/main/kotlin/dev/usbharu/hideout/routing/api/internal/v1/Users.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/routing/api/internal/v1/Users.kt
@@ -81,7 +81,7 @@ fun Route.users(userService: IUserService, userApiService: IUserApiService) {
                         }
                         val acct = AcctUtil.parse(userParameter)
                         val targetUser = userApiService.findByAcct(acct)
-                        if (userService.followRequest(targetUser.id, userId)) {
+                        if (userService.followRequest(targetUser.id.toLong(), userId)) {
                             return@post call.respond(HttpStatusCode.OK)
                         } else {
                             return@post call.respond(HttpStatusCode.Accepted)
diff --git a/src/main/resources/openapi/api.yaml b/src/main/resources/openapi/api.yaml
index e07dec94..840daedd 100644
--- a/src/main/resources/openapi/api.yaml
+++ b/src/main/resources/openapi/api.yaml
@@ -355,8 +355,7 @@ components:
       description: 投稿ID
       required: true
       schema:
-        type: integer
-        format: int64
+        type: string
     userName:
       name: userName
       in: path
@@ -385,8 +384,7 @@ components:
         - createdAt
       properties:
         id:
-          type: number
-          format: int64
+          type: string
           readOnly: true
         name:
           type: string
@@ -402,7 +400,7 @@ components:
           type: string
           readOnly: true
         createdAt:
-          type: number
+          type: integer
           readOnly: true
     PostResponse:
       type: object
@@ -416,8 +414,7 @@ components:
         - sensitive
       properties:
         id:
-          type: integer
-          format: int64
+          type: string
           readOnly: true
         user:
           $ref: "#/components/schemas/UserResponse"
@@ -436,12 +433,10 @@ components:
           format: uri
           readOnly: true
         repostId:
-          type: integer
-          format: int64
+          type: string
           readOnly: true
         replyId:
-          type: integer
-          format: int64
+          type: string
           readOnly: true
         sensitive:
           type: boolean
@@ -456,11 +451,9 @@ components:
         visibility:
           $ref: "#/components/schemas/Visibility"
         repostId:
-          type: integer
-          format: int64
+          type: string
         replyId:
-          type: integer
-          format: int64
+          type: string
         sensitive:
           type: boolean