diff --git a/back/volume/src/users/users.controller.ts b/back/volume/src/users/users.controller.ts
index f848880..9249c87 100644
--- a/back/volume/src/users/users.controller.ts
+++ b/back/volume/src/users/users.controller.ts
@@ -38,6 +38,16 @@ export class UsersController {
     return await this.usersService.findUsers()
   }
 
+  @Get('online')
+  async getOnlineUsers (): Promise<User[]> {
+    return await this.usersService.findOnlineUsers()
+  }
+
+  @Get(':id')
+  async getUser (@Param('id', ParseIntPipe) ftId: number): Promise<User> {
+    return await this.usersService.findUser(ftId)
+  }
+
   @Post()
   @UseGuards(AuthenticatedGuard)
   async create (@Body() payload: UserDto, @FtUser() profile: Profile) {
diff --git a/back/volume/src/users/users.service.ts b/back/volume/src/users/users.service.ts
index 694ea3b..a538bee 100644
--- a/back/volume/src/users/users.service.ts
+++ b/back/volume/src/users/users.service.ts
@@ -75,7 +75,7 @@ export class UsersService {
   async invit (ftId: number, targetFtId: number) {
     const user = await this.findUser(ftId)
     const target = await this.findUser(targetFtId)
-    if (!target) {
+    if (target == null) {
       return new NotFoundException(
         `Error: user id ${targetFtId} isn't in our db.`
       )
diff --git a/back/volume/tsconfig.json b/back/volume/tsconfig.json
index bdbebe4..35e1f74 100644
--- a/back/volume/tsconfig.json
+++ b/back/volume/tsconfig.json
@@ -13,6 +13,7 @@
     "incremental": true,
     "skipLibCheck": true,
     "alwaysStrict": true,
-    "noImplicitAny": true
+    "noImplicitAny": true,
+    "strictNullChecks": true
   }
 }