diff --git a/API/Controllers/AgeGroupController.cs b/API/Controllers/AgeGroupController.cs
index 89267d1..8280bf1 100644
--- a/API/Controllers/AgeGroupController.cs
+++ b/API/Controllers/AgeGroupController.cs
@@ -24,7 +24,7 @@ namespace API.Controllers
         }
 
         [HttpGet("{id}")]
-        public async Task<IActionResult> GetOne([FromRoute] int id)
+        public async Task<IActionResult> GetOne([FromRoute] string id)
         {
             var group = await _ageGroupService.GetAsync(id);
 
@@ -45,7 +45,7 @@ namespace API.Controllers
         }
 
         [HttpPut("{id}")]
-        public async Task<IActionResult> Update([FromRoute] int id, [FromBody] AltersGruppeIngoing groupDto)
+        public async Task<IActionResult> Update([FromRoute] string id, [FromBody] AltersGruppeIngoing groupDto)
         {
             var group = await _ageGroupService.UpdateAsync(id, groupDto.ToInternalFromIngoing());
 
@@ -58,7 +58,7 @@ namespace API.Controllers
         }
 
         [HttpDelete("{id}")]
-        public async Task<IActionResult> Delete([FromRoute] int Id)
+        public async Task<IActionResult> Delete([FromRoute] string Id)
         {
             var group = await _ageGroupService.DeleteAsync(Id);
 
diff --git a/API/Migrations/20251207192702_Init.Designer.cs b/API/Migrations/20251207192702_Init.Designer.cs
new file mode 100644
index 0000000..9426d12
--- /dev/null
+++ b/API/Migrations/20251207192702_Init.Designer.cs
@@ -0,0 +1,46 @@
+// <auto-generated />
+using API.Database;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace API.Migrations
+{
+    [DbContext(typeof(ApplicationDbContext))]
+    [Migration("20251207192702_Init")]
+    partial class Init
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "9.0.11");
+
+            modelBuilder.Entity("API.Models.Internal.Altersgruppen.AltersGruppe", b =>
+                {
+                    b.Property<string>("Id")
+                        .HasMaxLength(26)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("EndingAge")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("StartingAge")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Altersgruppen");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/API/Migrations/20251207192702_Init.cs b/API/Migrations/20251207192702_Init.cs
new file mode 100644
index 0000000..fb71bf2
--- /dev/null
+++ b/API/Migrations/20251207192702_Init.cs
@@ -0,0 +1,35 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace API.Migrations
+{
+    /// <inheritdoc />
+    public partial class Init : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "Altersgruppen",
+                columns: table => new
+                {
+                    Id = table.Column<string>(type: "TEXT", maxLength: 26, nullable: false),
+                    Name = table.Column<string>(type: "TEXT", maxLength: 100, nullable: false),
+                    StartingAge = table.Column<int>(type: "INTEGER", nullable: false),
+                    EndingAge = table.Column<int>(type: "INTEGER", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_Altersgruppen", x => x.Id);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "Altersgruppen");
+        }
+    }
+}
diff --git a/API/Migrations/ApplicationDbContextModelSnapshot.cs b/API/Migrations/ApplicationDbContextModelSnapshot.cs
new file mode 100644
index 0000000..cf69943
--- /dev/null
+++ b/API/Migrations/ApplicationDbContextModelSnapshot.cs
@@ -0,0 +1,43 @@
+// <auto-generated />
+using API.Database;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+
+#nullable disable
+
+namespace API.Migrations
+{
+    [DbContext(typeof(ApplicationDbContext))]
+    partial class ApplicationDbContextModelSnapshot : ModelSnapshot
+    {
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder.HasAnnotation("ProductVersion", "9.0.11");
+
+            modelBuilder.Entity("API.Models.Internal.Altersgruppen.AltersGruppe", b =>
+                {
+                    b.Property<string>("Id")
+                        .HasMaxLength(26)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("EndingAge")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(100)
+                        .HasColumnType("TEXT");
+
+                    b.Property<int>("StartingAge")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Altersgruppen");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/API/Repository/AgeGroup/AgeGroupService.cs b/API/Repository/AgeGroup/AgeGroupService.cs
index 5bdee6d..3b41cd6 100644
--- a/API/Repository/AgeGroup/AgeGroupService.cs
+++ b/API/Repository/AgeGroup/AgeGroupService.cs
@@ -20,7 +20,7 @@ namespace API.Repository.AgeGroup
             return altersGruppe;
         }
 
-        public async Task<AltersGruppe?> DeleteAsync(int id)
+        public async Task<AltersGruppe?> DeleteAsync(string id)
         {
             var group = await _context.Altersgruppen.FirstOrDefaultAsync(x => x.Id == id);
 
@@ -42,12 +42,12 @@ namespace API.Repository.AgeGroup
             return allGroups;
         }
 
-        public async Task<AltersGruppe?> GetAsync(int id)
+        public async Task<AltersGruppe?> GetAsync(string id)
         {
             return await _context.Altersgruppen.FindAsync(id);
         }
 
-        public async Task<AltersGruppe?> UpdateAsync(int id, AltersGruppe altersGruppe)
+        public async Task<AltersGruppe?> UpdateAsync(string id, AltersGruppe altersGruppe)
         {
             var existingGroup = await _context.Altersgruppen.FirstOrDefaultAsync(x => x.Id == id);
 
diff --git a/API/Repository/AgeGroup/IAgeGroupService.cs b/API/Repository/AgeGroup/IAgeGroupService.cs
index a350be0..9da50d3 100644
--- a/API/Repository/AgeGroup/IAgeGroupService.cs
+++ b/API/Repository/AgeGroup/IAgeGroupService.cs
@@ -6,9 +6,9 @@ namespace API.Repository.AgeGroup
     {
         public Task<List<AltersGruppe>> GetAllAsync();
 
-        public Task<AltersGruppe?> GetAsync(int id);
+        public Task<AltersGruppe?> GetAsync(string id);
         public Task<AltersGruppe> CreateAsync(AltersGruppe altersGruppe);
-        public Task<AltersGruppe?> DeleteAsync(int id);
-        public Task<AltersGruppe?> UpdateAsync(int id, AltersGruppe altersGruppe); 
+        public Task<AltersGruppe?> DeleteAsync(string id);
+        public Task<AltersGruppe?> UpdateAsync(string id, AltersGruppe altersGruppe); 
     }
 }
diff --git a/API/app.db b/API/app.db
new file mode 100644
index 0000000..0de02ec
Binary files /dev/null and b/API/app.db differ
diff --git a/API/app.db-shm b/API/app.db-shm
new file mode 100644
index 0000000..dc36e9f
Binary files /dev/null and b/API/app.db-shm differ
diff --git a/API/app.db-wal b/API/app.db-wal
new file mode 100644
index 0000000..930bbf5
Binary files /dev/null and b/API/app.db-wal differ