Diligent.WebAPI.Business/Extensions/FileExtensions.cs

+using Diligent.WebAPI.Contracts.DTOs.Files;
+
+namespace Diligent.WebAPI.Business.Extensions
+{
+    [ExcludeFromCodeCoverage]
+    public static class FileExtensions
+    {
+        public static IQueryable<FileEntity> FilterByExtension(this IQueryable<FileEntity> query, string[]? values)
+        {
+            if (values == null || values.Length == 0)
+                return query;
+            return query.Where(n => values.Contains(n.Extension));
+        }
+        public static IQueryable<FileEntity> FilterByCategory(this IQueryable<FileEntity> query, string[]? values)
+        {
+            if (values == null || values.Length == 0)
+                return query;
+            return query.Where(n => values.Contains(n.Category.Name));
+        }
+        public static IQueryable<FileEntity> FilterByTags(this IQueryable<FileEntity> query, string[]? values)
+        {
+            if (values == null || values.Length == 0)
+                return query;
+            //return query.Where(n => values.Any(x => n.Tags.Any(y => y.Name == x)));
+            return query.Where(n => n.Tags.Any(x => values.Contains(x.Name)));
+        }
+
+        public static IQueryable<FileEntity> FilterFiles(this IQueryable<FileEntity> query, FileFilter filters)
+        {
+            return query
+                .FilterByCategory(filters.Categories)
+                .FilterByExtension(filters.Extensions)
+                .FilterByTags(filters.Tags);
+        }
+    }
+}

Diligent.WebAPI.Business/Services/FileEntityService.cs

 using Azure.Core;
 using Diligent.WebAPI.Contracts.DTOs.File;
+using Diligent.WebAPI.Contracts.DTOs.Files;
 using System;
 using System.Collections.Generic;
 using System.Linq;
         {
             return await _context.Files.ToListAsync();
         }
+
+        public async Task<object> GetAllFiltered(FileFilter filters)
+        {
+            var filtered = await _context.Files
+                .Include(n => n.Tags)
+                .Include(n => n.Category)
+                .FilterFiles(filters)
+                .ToListAsync();
+
+            return new
+            {
+                Data = filtered.ApplyPagging(filters)
+                    .Select(n => new { n.Id, n.Name, n.Size, n.Extension}),
+                Total = filtered.Count
+            };
+        }
     }
 }

Diligent.WebAPI.Business/Services/Interfaces/IFileEntityService.cs

 using Diligent.WebAPI.Contracts.DTOs.File;
+using Diligent.WebAPI.Contracts.DTOs.Files;
 using System;
 using System.Collections.Generic;
 using System.Linq;
         Task<List<FileEntityResponse>> GetAllAsync();
         Task UploadPdfAsync(FileEntity file);
         Task<IEnumerable<FileEntity>> GetAll();
+        Task<object> GetAllFiltered(FileFilter filters);
     }
 }

Diligent.WebAPI.Contracts/DTOs/Files/FileFilter.cs

+using Diligent.WebAPI.Contracts.Models;
+
+namespace Diligent.WebAPI.Contracts.DTOs.Files
+{
+    public class FileFilter : Pagination
+    {
+        public string[]? Extensions { get; set; }
+        public string[]? Categories { get; set; }
+        public string[]? Tags { get; set; }
+    }
+}

Diligent.WebAPI.Host/Controllers/V1/FilesController.cs

 using Diligent.WebAPI.Contracts.DTOs.File;
+using Diligent.WebAPI.Contracts.DTOs.Files;
 using Diligent.WebAPI.Host.Methods;
 
 namespace Diligent.WebAPI.Host.Controllers.V1
         [HttpGet]
         public async Task<IActionResult> GetAll() => Ok(await _fileEntityService.GetAll());
 
+        [HttpGet("filtered")]
+        public async Task<IActionResult> GetAllFiltered([FromQuery] FileFilter filters) => Ok(await _fileEntityService.GetAllFiltered(filters));
+
         [HttpPost]
         public async Task<IActionResult> UploadPdf([FromForm] CreateFileRequest request)
         {