diff --git a/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/CreateCourseHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/CreateCourseHandler.cs
index 9325698a..7c51fac1 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/CreateCourseHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/CreateCourseHandler.cs
@@ -1,7 +1,7 @@
 using PIED_LMS.Contract.Abstractions.Storage;
 using PIED_LMS.Contract.Services.Course;
 using PIED_LMS.Contract.Services.Identity;
-using PIED_LMS.Application.UserCases;
+
 using PIED_LMS.Domain.Abstractions;
 
 namespace PIED_LMS.Application.UserCases.Commands.Course;
@@ -35,20 +35,7 @@ public async Task<ServiceResponse<Guid>> Handle(CreateCourseCommand request, Can
                 return new ServiceResponse<Guid>(false, errorMessage);
             }
 
-            var (curriculumJson, curriculumError) = CourseContentHelper.ValidateAndSerializeCurriculum(request.Curriculum);
-            if (curriculumError is not null)
-            {
-                logger.LogWarning("Course creation validation failed: {ValidationError}", curriculumError);
-                return new ServiceResponse<Guid>(false, curriculumError);
-            }
 
-            var insight = CourseContentHelper.ValidateAndNormalizeInsight(request.Insight);
-            if (insight is null)
-            {
-                const string errorMessage = "Insight is required and cannot be empty.";
-                logger.LogWarning("Course creation validation failed: {ValidationError}", errorMessage);
-                return new ServiceResponse<Guid>(false, errorMessage);
-            }
 
             // Subtask 5.4: Implement file upload and course creation
             string? thumbnailPath = null;
@@ -90,11 +77,39 @@ public async Task<ServiceResponse<Guid>> Handle(CreateCourseCommand request, Can
                 Seats = request.Seats,
                 Price = request.Price,
                 Value = request.Value,
-                Curriculum = curriculumJson,
-                Insight = insight,
                 CreatedAt = DateTime.UtcNow
             };
 
+            try
+            {
+                if (request.Curriculum != null)
+                {
+                    var domainCurriculum = request.Curriculum.Select(c => 
+                        new Domain.Entities.CurriculumSection(c.Title, c.Summary, c.Content)).ToList();
+                    course.SetCurriculum(domainCurriculum);
+                }
+                course.SetInsight(request.Insight);
+            }
+            catch (ArgumentException ex)
+            {
+                logger.LogWarning("Course creation validation failed: {ValidationError}", ex.Message);
+                
+                if (!string.IsNullOrEmpty(thumbnailPath))
+                {
+                    try
+                    {
+                        await fileStorageService.DeleteFileAsync(thumbnailPath, cancellationToken);
+                        logger.LogInformation("Deleted orphaned thumbnail {ThumbnailPath} after validation failure", thumbnailPath);
+                    }
+                    catch (Exception deleteEx)
+                    {
+                        logger.LogError(deleteEx, "Failed to delete orphaned thumbnail {ThumbnailPath}", thumbnailPath);
+                    }
+                }
+                
+                return new ServiceResponse<Guid>(false, ex.Message);
+            }
+
             // Add course to repository
             var repository = unitOfWork.Repository<Domain.Entities.Course>();
             await repository.AddAsync(course, cancellationToken);
diff --git a/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/UpdateCourseHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/UpdateCourseHandler.cs
index c495165d..11092896 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/UpdateCourseHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Commands/Course/UpdateCourseHandler.cs
@@ -1,7 +1,7 @@
 using PIED_LMS.Contract.Abstractions.Storage;
 using PIED_LMS.Contract.Services.Course;
 using PIED_LMS.Contract.Services.Identity;
-using PIED_LMS.Application.UserCases;
+
 using PIED_LMS.Domain.Abstractions;
 
 namespace PIED_LMS.Application.UserCases.Commands.Course;
@@ -37,21 +37,43 @@ public async Task<ServiceResponse<string>> Handle(UpdateCourseCommand request, C
                 return new ServiceResponse<string>(false, validationError);
             }
 
-            var (curriculumJson, curriculumError) = CourseContentHelper.ValidateAndSerializeCurriculum(request.Curriculum);
-            if (curriculumError is not null)
+
+
+            // Validate new slug uniqueness if slug changed
+            var newSlug = course.Slug;
+            if (!string.IsNullOrWhiteSpace(request.Slug) && request.Slug != course.Slug)
             {
-                logger.LogWarning("Course update validation failed for course {CourseId}: {ValidationError}",
-                    request.Id, curriculumError);
-                return new ServiceResponse<string>(false, curriculumError);
+                var slugToValidate = request.Slug.ToLowerInvariant().Trim();
+                var slugExists = await repository.AnyAsync(
+                    c => c.Slug == slugToValidate && c.Id != request.Id,
+                    cancellationToken);
+
+                if (slugExists)
+                {
+                    logger.LogWarning("Course update failed for course {CourseId}: Slug '{Slug}' already exists",
+                        request.Id, slugToValidate);
+                    return new ServiceResponse<string>(false, "Slug already exists. Please provide a unique slug.");
+                }
+
+                newSlug = slugToValidate;
             }
 
-            var insight = CourseContentHelper.ValidateAndNormalizeInsight(request.Insight);
-            if (insight is null)
+            // Validate Domain rules (Curriculum and Insight) before any side-effects
+            try
             {
-                const string errorMessage = "Insight is required and cannot be empty.";
-                logger.LogWarning("Course update validation failed for course {CourseId}: {ValidationError}",
-                    request.Id, errorMessage);
-                return new ServiceResponse<string>(false, errorMessage);
+                if (request.Curriculum != null)
+                {
+                    var domainCurriculum = request.Curriculum.Select(c => 
+                        new Domain.Entities.CurriculumSection(c.Title, c.Summary, c.Content)).ToList();
+                    course.SetCurriculum(domainCurriculum);
+                }
+                
+                course.SetInsight(request.Insight);
+            }
+            catch (ArgumentException ex)
+            {
+                logger.LogWarning("Course update validation failed for course {CourseId}: {ValidationError}", request.Id, ex.Message);
+                return new ServiceResponse<string>(false, ex.Message);
             }
 
             // Subtask 6.3: Implement thumbnail update logic
@@ -85,25 +107,6 @@ public async Task<ServiceResponse<string>> Handle(UpdateCourseCommand request, C
                 }
 
             // Subtask 6.4: Implement course update and commit
-            // Validate new slug uniqueness if slug changed
-            var newSlug = course.Slug;
-            if (!string.IsNullOrWhiteSpace(request.Slug) && request.Slug != course.Slug)
-            {
-                var slugToValidate = request.Slug.ToLowerInvariant().Trim();
-                var slugExists = await repository.AnyAsync(
-                    c => c.Slug == slugToValidate && c.Id != request.Id,
-                    cancellationToken);
-
-                if (slugExists)
-                {
-                    logger.LogWarning("Course update failed for course {CourseId}: Slug '{Slug}' already exists",
-                        request.Id, slugToValidate);
-                    return new ServiceResponse<string>(false, "Slug already exists. Please provide a unique slug.");
-                }
-
-                newSlug = slugToValidate;
-            }
-
             // Track changed properties for logging
             var changedProperties = new List<string>();
             if (course.Title != request.Title) changedProperties.Add($"Title: '{course.Title}' -> '{request.Title}'");
@@ -113,8 +116,6 @@ public async Task<ServiceResponse<string>> Handle(UpdateCourseCommand request, C
             if (course.Status != request.Status) changedProperties.Add($"Status: {course.Status} -> {request.Status}");
             if (course.Slug != newSlug) changedProperties.Add($"Slug: '{course.Slug}' -> '{newSlug}'");
             if (course.ThumbnailPath != newThumbnailPath) changedProperties.Add("ThumbnailPath");
-            if (course.Curriculum != curriculumJson) changedProperties.Add("Curriculum");
-            if (course.Insight != insight) changedProperties.Add("Insight");
 
             // Update course properties
             course.Title = request.Title;
@@ -131,8 +132,6 @@ public async Task<ServiceResponse<string>> Handle(UpdateCourseCommand request, C
             course.Seats = request.Seats;
             course.Price = request.Price;
             course.Value = request.Value;
-            course.Curriculum = curriculumJson;
-            course.Insight = insight;
             course.UpdatedAt = DateTime.UtcNow;
 
             // Update course in repository
diff --git a/backend/Src/PIED_LMS.Application/UserCases/CourseContentHelper.cs b/backend/Src/PIED_LMS.Application/UserCases/CourseContentHelper.cs
deleted file mode 100644
index 309edc1b..00000000
--- a/backend/Src/PIED_LMS.Application/UserCases/CourseContentHelper.cs
+++ /dev/null
@@ -1,73 +0,0 @@
-using System.Text.Json;
-using PIED_LMS.Contract.Services.Course;
-
-namespace PIED_LMS.Application.UserCases;
-
-public static class CourseContentHelper
-{
-    private static readonly JsonSerializerOptions JsonOptions = new()
-    {
-        PropertyNameCaseInsensitive = true
-    };
-
-    public static (string? CurriculumJson, string? Error) ValidateAndSerializeCurriculum(string? curriculum)
-    {
-        if (string.IsNullOrWhiteSpace(curriculum))
-            return (null, "Curriculum is required and cannot be empty.");
-
-        List<CurriculumSectionDto> sections;
-        try
-        {
-            sections = JsonSerializer.Deserialize<List<CurriculumSectionDto>>(curriculum, JsonOptions)
-                       ?? [];
-        }
-        catch (JsonException)
-        {
-            return (null, "Curriculum must be a valid JSON array of sections.");
-        }
-
-        for (var i = 0; i < sections.Count; i++)
-        {
-            var section = sections[i];
-            if (string.IsNullOrWhiteSpace(section.Title))
-                return (null, $"Curriculum section {i + 1} must have a title.");
-
-            if (string.IsNullOrWhiteSpace(section.Summary))
-                return (null, $"Curriculum section {i + 1} must have a summary.");
-
-            if (section.Content is null || section.Content.Count == 0 ||
-                section.Content.All(string.IsNullOrWhiteSpace))
-                return (null, $"Curriculum section {i + 1} must have at least one content item.");
-        }
-
-        return (JsonSerializer.Serialize(sections, JsonOptions), null);
-    }
-
-    public static string? ValidateAndNormalizeInsight(string? insight)
-    {
-        if (string.IsNullOrWhiteSpace(insight))
-            return null;
-
-        return insight.Trim();
-    }
-
-    public static List<CurriculumSectionDto> DeserializeCurriculum(
-        string? curriculum,
-        ILogger logger,
-        Guid courseId)
-    {
-        if (string.IsNullOrWhiteSpace(curriculum))
-            return [];
-
-        try
-        {
-            return JsonSerializer.Deserialize<List<CurriculumSectionDto>>(curriculum, JsonOptions)
-                   ?? [];
-        }
-        catch (JsonException ex)
-        {
-            logger.LogError(ex, "Failed to parse curriculum JSON for course {CourseId}", courseId);
-            return [];
-        }
-    }
-}
diff --git a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseByIdHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseByIdHandler.cs
index f8fd6586..dddd34c1 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseByIdHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseByIdHandler.cs
@@ -2,7 +2,7 @@
 using PIED_LMS.Contract.Abstractions.Storage;
 using PIED_LMS.Contract.Services.Course;
 using PIED_LMS.Contract.Services.Identity;
-using PIED_LMS.Application.UserCases;
+
 using PIED_LMS.Domain.Abstractions;
 
 namespace PIED_LMS.Application.UserCases.Queries.Course;
@@ -108,7 +108,8 @@ private async Task<CourseDto> MapToCourseDto(Domain.Entities.Course course, Canc
             t.ProfilePictureUrl
         )).ToList();
 
-        var curriculum = CourseContentHelper.DeserializeCurriculum(course.Curriculum, logger, course.Id);
+        var curriculumDto = course.Curriculum?.Select(c => 
+            new CurriculumSectionDto(c.Title, c.Summary, c.Content.ToList())).ToList() ?? new List<CurriculumSectionDto>();
 
         return new CourseDto(
             course.Id,
@@ -127,7 +128,7 @@ private async Task<CourseDto> MapToCourseDto(Domain.Entities.Course course, Canc
             course.CreatedAt,
             course.UpdatedAt,
             course.Value,
-            curriculum,
+            curriculumDto,
             course.Insight ?? string.Empty
         );
     }
diff --git a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseCurriculumHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseCurriculumHandler.cs
index 5fbe146b..96327abd 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseCurriculumHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCourseCurriculumHandler.cs
@@ -1,6 +1,6 @@
 using PIED_LMS.Contract.Services.Course;
 using PIED_LMS.Contract.Services.Identity;
-using PIED_LMS.Application.UserCases;
+
 using PIED_LMS.Domain.Abstractions;
 
 namespace PIED_LMS.Application.UserCases.Queries.Course;
@@ -28,12 +28,13 @@ public async Task<ServiceResponse<List<CurriculumSectionDto>>> Handle(
                 );
             }
 
-            var curriculum = CourseContentHelper.DeserializeCurriculum(course.Curriculum, logger, course.Id);
+            var curriculumDto = course.Curriculum?.Select(c => 
+                new CurriculumSectionDto(c.Title, c.Summary, c.Content.ToList())).ToList() ?? new List<CurriculumSectionDto>();
 
             return new ServiceResponse<List<CurriculumSectionDto>>(
                 true,
                 "Curriculum retrieved successfully",
-                curriculum
+                curriculumDto
             );
         }
         catch (Exception ex)
diff --git a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCoursesHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCoursesHandler.cs
index d75f5d7d..71ade96d 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCoursesHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Queries/Course/GetCoursesHandler.cs
@@ -2,7 +2,7 @@
 using PIED_LMS.Contract.Abstractions.Storage;
 using PIED_LMS.Contract.Services.Course;
 using PIED_LMS.Contract.Services.Identity;
-using PIED_LMS.Application.UserCases;
+
 using PIED_LMS.Domain.Abstractions;
 
 namespace PIED_LMS.Application.UserCases.Queries.Course;
@@ -119,7 +119,8 @@ private async Task<CourseDto> MapToCourseDto(Domain.Entities.Course course, Canc
                 t.ProfilePictureUrl
             )).ToList();
 
-        var curriculum = CourseContentHelper.DeserializeCurriculum(course.Curriculum, logger, course.Id);
+        var curriculumDto = course.Curriculum?.Select(c => 
+            new CurriculumSectionDto(c.Title, c.Summary, c.Content.ToList())).ToList() ?? new List<CurriculumSectionDto>();
 
         return new CourseDto(
             course.Id,
@@ -138,7 +139,7 @@ private async Task<CourseDto> MapToCourseDto(Domain.Entities.Course course, Canc
             course.CreatedAt,
             course.UpdatedAt,
             course.Value,
-            curriculum,
+            curriculumDto,
             course.Insight ?? string.Empty
         );
     }
diff --git a/backend/Src/PIED_LMS.Application/UserCases/Queries/GetUserByIdHandler.cs b/backend/Src/PIED_LMS.Application/UserCases/Queries/GetUserByIdHandler.cs
index a72bfd5d..55395b6d 100644
--- a/backend/Src/PIED_LMS.Application/UserCases/Queries/GetUserByIdHandler.cs
+++ b/backend/Src/PIED_LMS.Application/UserCases/Queries/GetUserByIdHandler.cs
@@ -1,6 +1,6 @@
 using PIED_LMS.Contract.Abstractions.Storage;
-using PIED_LMS.Contract.Abstractions.Storage;
 using PIED_LMS.Contract.Services.Identity;
+using PIED_LMS.Domain.Abstractions;
 using PIED_LMS.Domain.Entities;
 
 namespace PIED_LMS.Application.UserCases.Queries;
diff --git a/backend/Src/PIED_LMS.Contract/Services/Course/Command.cs b/backend/Src/PIED_LMS.Contract/Services/Course/Command.cs
index fbdc1876..6dfdcbc7 100644
--- a/backend/Src/PIED_LMS.Contract/Services/Course/Command.cs
+++ b/backend/Src/PIED_LMS.Contract/Services/Course/Command.cs
@@ -19,8 +19,8 @@ public record CreateCourseCommand(
     string? Seats,
     string? Price,
     int Value,
-    string? Curriculum,
-    string? Insight
+    List<CurriculumSectionDto>? Curriculum,
+    string Insight
 ) : IRequest<ServiceResponse<Guid>>;
 
 // Update Course Command
@@ -38,8 +38,8 @@ public record UpdateCourseCommand(
     string? Seats,
     string? Price,
     int Value,
-    string? Curriculum,
-    string? Insight
+    List<CurriculumSectionDto>? Curriculum,
+    string Insight
 ) : IRequest<ServiceResponse<string>>;
 
 // Delete Course Command
diff --git a/backend/Src/PIED_LMS.Contract/Services/Course/Request.cs b/backend/Src/PIED_LMS.Contract/Services/Course/Request.cs
index 803fd7fe..e11474e8 100644
--- a/backend/Src/PIED_LMS.Contract/Services/Course/Request.cs
+++ b/backend/Src/PIED_LMS.Contract/Services/Course/Request.cs
@@ -18,7 +18,7 @@ public sealed record CreateCourseRequest(
     [FromForm(Name = "seats")] string? Seats,
     [FromForm(Name = "price")] string? Price,
     [FromForm(Name = "value")] int Value,
-    [FromForm(Name = "curriculum")] string? Curriculum,
+    [FromForm(Name = "curriculum")] List<CurriculumSectionDto>? Curriculum,
     [FromForm(Name = "insight")]
     [Required(ErrorMessage = "Insight is required and cannot be empty.")]
     string Insight
@@ -37,7 +37,7 @@ public sealed record UpdateCourseRequest(
     [FromForm(Name = "seats")] string? Seats,
     [FromForm(Name = "price")] string? Price,
     [FromForm(Name = "value")] int Value,
-    [FromForm(Name = "curriculum")] string? Curriculum,
+    [FromForm(Name = "curriculum")] List<CurriculumSectionDto>? Curriculum,
     [FromForm(Name = "insight")]
     [Required(ErrorMessage = "Insight is required and cannot be empty.")]
     string Insight
diff --git a/backend/Src/PIED_LMS.Domain/Entities/Course.cs b/backend/Src/PIED_LMS.Domain/Entities/Course.cs
index f628d831..9d363f9c 100644
--- a/backend/Src/PIED_LMS.Domain/Entities/Course.cs
+++ b/backend/Src/PIED_LMS.Domain/Entities/Course.cs
@@ -21,8 +21,8 @@ public class Course
     public string? Price { get; set; }
     public int Value { get; set; }
 
-    public string? Curriculum { get; set; }
-    public string? Insight { get; set; }
+    public List<CurriculumSection> Curriculum { get; private set; } = new();
+    public string? Insight { get; private set; }
 
     public int MaxCapacity { get; set; }
     public int CurrentEnrollment { get; set; }
@@ -34,4 +34,17 @@ public class Course
     // Self-referencing many-to-many for prerequisites
     public ICollection<Course> PrerequisiteCourses { get; set; } = new List<Course>();
     public ICollection<Course> PrerequisiteFor { get; set; } = new List<Course>();
+
+    public void SetCurriculum(List<CurriculumSection>? curriculum)
+    {
+        Curriculum = curriculum ?? new List<CurriculumSection>();
+    }
+
+    public void SetInsight(string insight)
+    {
+        if (string.IsNullOrWhiteSpace(insight))
+            throw new ArgumentException("Insight is required and cannot be empty.");
+            
+        Insight = insight.Trim();
+    }
 }
diff --git a/backend/Src/PIED_LMS.Domain/Entities/CurriculumSection.cs b/backend/Src/PIED_LMS.Domain/Entities/CurriculumSection.cs
new file mode 100644
index 00000000..2862e3de
--- /dev/null
+++ b/backend/Src/PIED_LMS.Domain/Entities/CurriculumSection.cs
@@ -0,0 +1,32 @@
+namespace PIED_LMS.Domain.Entities;
+
+public class CurriculumSection
+{
+    public string Title { get; private set; }
+    public string Summary { get; private set; }
+    public IReadOnlyList<string> Content { get; private set; }
+
+    // Required for EF Core serialization/deserialization or default instantiation
+    private CurriculumSection() 
+    { 
+        Title = null!;
+        Summary = null!;
+        Content = null!;
+    }
+
+    public CurriculumSection(string title, string summary, List<string> content)
+    {
+        if (string.IsNullOrWhiteSpace(title))
+            throw new ArgumentException("Curriculum section must have a title.");
+        
+        if (string.IsNullOrWhiteSpace(summary))
+            throw new ArgumentException("Curriculum section must have a summary.");
+        
+        if (content == null || content.Count == 0 || content.All(string.IsNullOrWhiteSpace))
+            throw new ArgumentException("Curriculum section must have at least one valid content item.");
+
+        Title = title;
+        Summary = summary;
+        Content = new List<string>(content).AsReadOnly();
+    }
+}
diff --git a/backend/Src/PIED_LMS.Persistence/Configurations/CourseConfiguration.cs b/backend/Src/PIED_LMS.Persistence/Configurations/CourseConfiguration.cs
index 39d47dd2..ba0bed84 100644
--- a/backend/Src/PIED_LMS.Persistence/Configurations/CourseConfiguration.cs
+++ b/backend/Src/PIED_LMS.Persistence/Configurations/CourseConfiguration.cs
@@ -1,3 +1,4 @@
+using System.Text.Json;
 using PIED_LMS.Domain.Entities;
 
 namespace PIED_LMS.Persistence.Configurations;
@@ -54,6 +55,18 @@ public void Configure(EntityTypeBuilder<Course> builder)
             .IsRequired()
             .HasDefaultValue(0);
 
+        var jsonOptions = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };
+        builder.Property(c => c.Curriculum)
+            .HasConversion(
+                v => JsonSerializer.Serialize(v, jsonOptions),
+                v => string.IsNullOrWhiteSpace(v) 
+                    ? new List<CurriculumSection>() 
+                    : JsonSerializer.Deserialize<List<CurriculumSection>>(v, jsonOptions) ?? new List<CurriculumSection>()
+            );
+
+        builder.Property(c => c.Insight)
+            .IsRequired(false); // Can be configured as needed
+
         // Many-to-many relationship for Prerequisites
         builder.HasMany(c => c.PrerequisiteCourses)
             .WithMany(c => c.PrerequisiteFor)