diff --git a/backend/Controllers/MovieController.cs b/backend/Controllers/MovieController.cs
index 133640e..b87ac19 100644
--- a/backend/Controllers/MovieController.cs
+++ b/backend/Controllers/MovieController.cs
@@ -1,7 +1,8 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.OpenApi.Writers;
 
-namespace backend.Controllers;
+namespace backend;
+using static backend.QueryParameterValidators;
 
 [ApiController]
 [Route("[controller]")]
@@ -9,6 +10,10 @@ public class MovieController: ControllerBase
 {
     private readonly MovieDbContext _context;
     private readonly ILogger<MovieController> _logger;
+    private static readonly string[] sortTypes = new[]
+    {
+        "titleasc", "titledesc", "yearasc", "yeardesc"
+    };
 
     public MovieController(ILogger<MovieController> logger, MovieDbContext context)
     {
@@ -18,31 +23,39 @@ public class MovieController: ControllerBase
 
     [HttpGet(Name = "GetMovies")]
     public ActionResult<IEnumerable<MovieDB>> Get(
-        [FromQuery] string? s,
+        [FromQuery] string s,
         [FromQuery] string? type,
         [FromQuery] string? y,
+        [FromQuery] string? sort,
         [FromQuery] int pageNumber = 1, 
         [FromQuery] int pageSize = 5
     ) {
     try
         {
-            if (s == "") {
-                return StatusCode(400, "Bad Request");
-            }
-            
+            if (IsValidS(s)) return StatusCode(400, "Bad Request: Invalid title");
             var movies = _context.Movies.Where(m => m.Title.Contains(s.ToLower()));
 
             if (type != null) {
+                if (!IsValidType(type)) return StatusCode(400, "Bad Request: Invalid type");
                 movies = movies.Where(m => m.Type == type);
             }
 
             if (y != null) {
+                if (!IsValidYear(y)) return StatusCode(400, "Bad Request: Invalid year");
                 movies = movies.Where(m => m.Year == y);
             }
 
+            if (sort != null) {
+                if (!IsValidSort(sort)) return StatusCode(400, "Bad Request: Invalid sort-type");
+                
+            }
+
+            if (!IsValidPageNumber(pageNumber) || !IsValidPageSize(pageSize)) 
+                return StatusCode(400, "Bad Request: Invalid page-size or page-number");
+
             var totalMovies = movies.Count();
             var totalPages = Math.Ceiling((double)totalMovies / pageSize);
-
+            
             IEnumerable<MovieDB> resultSkip = movies.Skip(pageSize * (pageNumber - 1));
             IEnumerable<MovieDB> resultTake = resultSkip.Take(pageSize);