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 7e73a81f..e74a4a72 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
@@ -1,5 +1,7 @@
 package dev.usbharu.hideout.domain.model.hideout.dto
 
+import dev.usbharu.hideout.domain.model.hideout.entity.User
+
 data class UserResponse(
     val id: Long,
     val name: String,
@@ -8,4 +10,18 @@ data class UserResponse(
     val description: String = "",
     val url: String,
     val createdAt: Long
-)
+) {
+    companion object {
+        fun from(user: User): UserResponse {
+            return UserResponse(
+                user.id,
+                user.name,
+                user.domain,
+                user.screenName,
+                user.description,
+                user.url,
+                user.createdAt.toEpochMilli()
+            )
+        }
+    }
+}
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 a4bea389..92297e11 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
@@ -5,6 +5,7 @@ import dev.usbharu.hideout.domain.model.hideout.dto.UserCreateDto
 import dev.usbharu.hideout.domain.model.hideout.form.UserCreate
 import dev.usbharu.hideout.exception.ParameterNotExistException
 import dev.usbharu.hideout.plugins.TOKEN_AUTH
+import dev.usbharu.hideout.service.IUserApiService
 import dev.usbharu.hideout.service.impl.IUserService
 import dev.usbharu.hideout.util.AcctUtil
 import io.ktor.http.*
@@ -15,10 +16,10 @@ import io.ktor.server.request.*
 import io.ktor.server.response.*
 import io.ktor.server.routing.*
 
-fun Route.users(userService: IUserService) {
+fun Route.users(userService: IUserService, userApiService: IUserApiService) {
     route("/users") {
         get {
-            call.respond(userService.findAllForUser())
+            call.respond(userApiService.findAll())
         }
         post {
             val userCreate = call.receive<UserCreate>()
@@ -43,10 +44,10 @@ fun Route.users(userService: IUserService) {
                     val userParameter = (call.parameters["name"]
                         ?: throw ParameterNotExistException("Parameter(name='userName@domain') does not exist."))
                     if (userParameter.toLongOrNull() != null) {
-                        return@get call.respond(userService.findById(userParameter.toLong()))
+                        return@get call.respond(userApiService.findById(userParameter.toLong()))
                     } else {
                         val acct = AcctUtil.parse(userParameter)
-                        return@get call.respond(userService.findByNameAndDomain(acct.username, acct.domain))
+                        return@get call.respond(userApiService.findByAcct(acct))
                     }
                 }
             }
@@ -56,10 +57,10 @@ fun Route.users(userService: IUserService) {
                     val userParameter = call.parameters["name"]
                         ?: throw ParameterNotExistException("Parameter(name='userName@domain') does not exist.")
                     if (userParameter.toLongOrNull() != null) {
-                        return@get call.respond(userService.findFollowersById(userParameter.toLong()))
+                        return@get call.respond(userApiService.findFollowers(userParameter.toLong()))
                     }
                     val acct = AcctUtil.parse(userParameter)
-                    return@get call.respond(userService.findFollowersByNameAndDomain(acct.username, acct.domain))
+                    return@get call.respond(userApiService.findFollowersByAcct(acct))
                 }
                 authenticate(TOKEN_AUTH) {
 
@@ -76,7 +77,7 @@ fun Route.users(userService: IUserService) {
                             }
                         }
                         val acct = AcctUtil.parse(userParameter)
-                        val targetUser = userService.findByNameAndDomain(acct.username, acct.domain)
+                        val targetUser = userApiService.findByAcct(acct)
                         if (userService.addFollowers(targetUser.id, userId)) {
                             return@post call.respond(HttpStatusCode.OK)
                         } else {
@@ -90,10 +91,10 @@ fun Route.users(userService: IUserService) {
                     val userParameter = (call.parameters["name"]
                         ?: throw ParameterNotExistException("Parameter(name='userName@domain') does not exist."))
                     if (userParameter.toLongOrNull() != null) {
-                        return@get call.respond(userService.findFollowingById(userParameter.toLong()))
+                        return@get call.respond(userApiService.findFollowings(userParameter.toLong()))
                     }
                     val acct = AcctUtil.parse(userParameter)
-                    return@get call.respond(userService.findFollowingByNameAndDomain(acct.username, acct.domain))
+                    return@get call.respond(userApiService.findFollowingsByAcct(acct))
                 }
             }
         }
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/IUserApiService.kt b/src/main/kotlin/dev/usbharu/hideout/service/IUserApiService.kt
new file mode 100644
index 00000000..dd79e471
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/service/IUserApiService.kt
@@ -0,0 +1,24 @@
+package dev.usbharu.hideout.service
+
+import dev.usbharu.hideout.domain.model.Acct
+import dev.usbharu.hideout.domain.model.hideout.dto.UserResponse
+
+interface IUserApiService {
+    suspend fun findAll(limit: Int? = 100, offset: Long = 0): List<UserResponse>
+
+    suspend fun findById(id: Long): UserResponse
+
+    suspend fun findByIds(ids: List<Long>): List<UserResponse>
+
+    suspend fun findByAcct(acct: Acct): UserResponse
+
+    suspend fun findByAccts(accts: List<Acct>): List<UserResponse>
+
+    suspend fun findFollowers(userId: Long): List<UserResponse>
+
+    suspend fun findFollowings(userId: Long): List<UserResponse>
+
+    suspend fun findFollowersByAcct(acct: Acct): List<UserResponse>
+
+    suspend fun findFollowingsByAcct(acct: Acct): List<UserResponse>
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/UserApiServiceImpl.kt b/src/main/kotlin/dev/usbharu/hideout/service/UserApiServiceImpl.kt
new file mode 100644
index 00000000..f3e70e10
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/service/UserApiServiceImpl.kt
@@ -0,0 +1,38 @@
+package dev.usbharu.hideout.service
+
+import dev.usbharu.hideout.config.Config
+import dev.usbharu.hideout.domain.model.Acct
+import dev.usbharu.hideout.domain.model.hideout.dto.UserResponse
+import dev.usbharu.hideout.service.impl.IUserService
+import org.koin.core.annotation.Single
+
+@Single
+class UserApiServiceImpl(private val userService: IUserService) : IUserApiService {
+    override suspend fun findAll(limit: Int?, offset: Long): List<UserResponse> =
+        userService.findAll(limit, offset).map { UserResponse.from(it) }
+
+    override suspend fun findById(id: Long): UserResponse = UserResponse.from(userService.findById(id))
+
+    override suspend fun findByIds(ids: List<Long>): List<UserResponse> =
+        userService.findByIds(ids).map { UserResponse.from(it) }
+
+    override suspend fun findByAcct(acct: Acct): UserResponse =
+        UserResponse.from(userService.findByNameAndDomain(acct.username, acct.domain))
+
+    override suspend fun findByAccts(accts: List<Acct>): List<UserResponse> {
+        return userService.findByNameAndDomains(accts.map { it.username to (it.domain ?: Config.configData.domain) })
+            .map { UserResponse.from(it) }
+    }
+
+    override suspend fun findFollowers(userId: Long): List<UserResponse> =
+        userService.findFollowersById(userId).map { UserResponse.from(it) }
+
+    override suspend fun findFollowings(userId: Long): List<UserResponse> =
+        userService.findFollowingById(userId).map { UserResponse.from(it) }
+
+    override suspend fun findFollowersByAcct(acct: Acct): List<UserResponse> =
+        userService.findFollowersByNameAndDomain(acct.username, acct.domain).map { UserResponse.from(it) }
+
+    override suspend fun findFollowingsByAcct(acct: Acct): List<UserResponse> =
+        userService.findFollowingByNameAndDomain(acct.username, acct.domain).map { UserResponse.from(it) }
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/impl/IUserService.kt b/src/main/kotlin/dev/usbharu/hideout/service/impl/IUserService.kt
index 1fc6922e..ab726ac1 100644
--- a/src/main/kotlin/dev/usbharu/hideout/service/impl/IUserService.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/service/impl/IUserService.kt
@@ -2,15 +2,12 @@ package dev.usbharu.hideout.service.impl
 
 import dev.usbharu.hideout.domain.model.hideout.dto.RemoteUserCreateDto
 import dev.usbharu.hideout.domain.model.hideout.dto.UserCreateDto
-import dev.usbharu.hideout.domain.model.hideout.dto.UserResponse
 import dev.usbharu.hideout.domain.model.hideout.entity.User
 
 @Suppress("TooManyFunctions")
 interface IUserService {
     suspend fun findAll(limit: Int? = 100, offset: Long? = 0): List<User>
 
-    suspend fun findAllForUser(limit: Int? = 100, offset: Long? = 0): List<UserResponse>
-
     suspend fun findById(id: Long): User
 
     suspend fun findByIds(ids: List<Long>): List<User>
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/impl/UserService.kt b/src/main/kotlin/dev/usbharu/hideout/service/impl/UserService.kt
index b4f3157c..1500d145 100644
--- a/src/main/kotlin/dev/usbharu/hideout/service/impl/UserService.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/service/impl/UserService.kt
@@ -24,7 +24,7 @@ class UserService(private val userRepository: IUserRepository, private val userA
         )
     }
 
-    override suspend fun findAllForUser(limit: Int?, offset: Long?): List<UserResponse> {
+    suspend fun findAllForUser(limit: Int?, offset: Long?): List<UserResponse> {
         TODO("Not yet implemented")
     }
 
diff --git a/src/main/resources/openapi/documentation.yaml b/src/main/resources/openapi/documentation.yaml
index d4e6d624..6c90a035 100644
--- a/src/main/resources/openapi/documentation.yaml
+++ b/src/main/resources/openapi/documentation.yaml
@@ -112,6 +112,15 @@ paths:
           required: false
           schema:
             type: "integer"
+      responses:
+        "200":
+          description: "OK"
+          content:
+            '*/*':
+              schema:
+                type: "array"
+                items:
+                  $ref: "#/components/schemas/Post"
     post:
       description: ""
       requestBody:
@@ -127,6 +136,61 @@ paths:
             '*/*':
               schema:
                 type: "object"
+  /api/internal/v1/posts/{id}:
+    get:
+      description: ""
+      parameters:
+        - name: "id"
+          in: "path"
+          required: true
+          schema:
+            type: "number"
+      responses:
+        "200":
+          description: "OK"
+          content:
+            '*/*':
+              schema:
+                $ref: "#/components/schemas/Post"
+  /api/internal/v1/users/{name}/posts:
+    get:
+      description: ""
+      parameters:
+        - name: "name"
+          in: "path"
+          required: true
+          schema:
+            type: "string"
+      responses:
+        "200":
+          description: "OK"
+          content:
+            '*/*':
+              schema:
+                type: "array"
+                items:
+                  $ref: "#/components/schemas/Post"
+  /api/internal/v1/users/{name}/posts/{id}:
+    get:
+      description: ""
+      parameters:
+        - name: "id"
+          in: "path"
+          required: true
+          schema:
+            type: "number"
+        - name: "name"
+          in: "path"
+          required: true
+          schema:
+            type: "string"
+      responses:
+        "200":
+          description: "OK"
+          content:
+            '*/*':
+              schema:
+                $ref: "#/components/schemas/Post"
   /inbox:
     get:
       description: ""
@@ -346,10 +410,19 @@ components:
     Post:
       type: "object"
       properties:
-        text:
-          type: "string"
+        id:
+          type: "integer"
+          format: "int64"
+        userId:
+          type: "integer"
+          format: "int64"
         overview:
           type: "string"
+        text:
+          type: "string"
+        createdAt:
+          type: "integer"
+          format: "int64"
         visibility:
           type: "string"
           enum:
@@ -357,6 +430,8 @@ components:
             - "UNLISTED"
             - "FOLLOWERS"
             - "DIRECT"
+        url:
+          type: "string"
         repostId:
           type: "integer"
           format: "int64"