diff --git a/.claude/scheduled_tasks.lock b/.claude/scheduled_tasks.lock
index 1d16352..408ae32 100644
--- a/.claude/scheduled_tasks.lock
+++ b/.claude/scheduled_tasks.lock
@@ -1 +1 @@
-{"sessionId":"49d9d3ba-3c81-4fe7-ab85-f0734baf92f6","pid":42320,"acquiredAt":1782462035015}
\ No newline at end of file
+{"sessionId":"c3cb93c0-7adf-4d3a-817d-6c01e0e0f09f","pid":26816,"acquiredAt":1782481349474}
\ No newline at end of file
diff --git a/TaxBaik.Application/DependencyInjection.cs b/TaxBaik.Application/DependencyInjection.cs
index 324ecf3..ae0bf2b 100644
--- a/TaxBaik.Application/DependencyInjection.cs
+++ b/TaxBaik.Application/DependencyInjection.cs
@@ -9,6 +9,7 @@ public static class DependencyInjection
     {
         services.AddScoped<BlogService>();
         services.AddScoped<InquiryService>();
+        services.AddScoped<CategoryService>();
         return services;
     }
 }
diff --git a/TaxBaik.Application/Services/BlogService.cs b/TaxBaik.Application/Services/BlogService.cs
index 2091ba3..7d65791 100644
--- a/TaxBaik.Application/Services/BlogService.cs
+++ b/TaxBaik.Application/Services/BlogService.cs
@@ -1,6 +1,7 @@
 namespace TaxBaik.Application.Services;
 
 using System.Text.RegularExpressions;
+using TaxBaik.Application.DTOs;
 using TaxBaik.Domain.Entities;
 using TaxBaik.Domain.Interfaces;
 
@@ -13,6 +14,9 @@ public class BlogService(IBlogPostRepository repository)
         int page, int pageSize, int? categoryId = null, CancellationToken ct = default) =>
         await repository.GetPublishedPagedAsync(page, pageSize, categoryId, ct);
 
+    public async Task<IEnumerable<BlogPost>> GetAllAsync(CancellationToken ct = default) =>
+        await repository.GetAllForAdminAsync(ct);
+
     public async Task<IEnumerable<BlogPost>> GetAllForAdminAsync(CancellationToken ct = default) =>
         await repository.GetAllForAdminAsync(ct);
 
@@ -23,9 +27,49 @@ public class BlogService(IBlogPostRepository repository)
         return await repository.CreateAsync(post, ct);
     }
 
+    public async Task<BlogPost> CreateAsync(CreateBlogPostDto dto, CancellationToken ct = default)
+    {
+        var post = new BlogPost
+        {
+            Title = dto.Title,
+            Content = dto.Content,
+            CategoryId = dto.CategoryId,
+            Tags = dto.Tags,
+            SeoTitle = dto.SeoTitle,
+            SeoDescription = dto.SeoDescription,
+            ThumbnailUrl = dto.ThumbnailUrl,
+            IsPublished = dto.IsPublished,
+            AuthorId = dto.AuthorId,
+            CreatedAt = DateTime.UtcNow
+        };
+
+        var id = await CreateAsync(post, ct);
+        post.Id = id;
+        return post;
+    }
+
     public async Task UpdateAsync(BlogPost post, CancellationToken ct = default) =>
         await repository.UpdateAsync(post, ct);
 
+    public async Task<BlogPost?> UpdateAsync(int id, CreateBlogPostDto dto, CancellationToken ct = default)
+    {
+        var post = await repository.GetByIdAsync(id, ct);
+        if (post == null)
+            return null;
+
+        post.Title = dto.Title;
+        post.Content = dto.Content;
+        post.CategoryId = dto.CategoryId;
+        post.Tags = dto.Tags;
+        post.SeoTitle = dto.SeoTitle;
+        post.SeoDescription = dto.SeoDescription;
+        post.ThumbnailUrl = dto.ThumbnailUrl;
+        post.IsPublished = dto.IsPublished;
+
+        await UpdateAsync(post, ct);
+        return post;
+    }
+
     public async Task DeleteAsync(int id, CancellationToken ct = default) =>
         await repository.DeleteAsync(id, ct);
 
diff --git a/TaxBaik.Application/Services/CategoryService.cs b/TaxBaik.Application/Services/CategoryService.cs
new file mode 100644
index 0000000..dc76692
--- /dev/null
+++ b/TaxBaik.Application/Services/CategoryService.cs
@@ -0,0 +1,54 @@
+namespace TaxBaik.Application.Services;
+
+using System.Text.RegularExpressions;
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class CategoryService(ICategoryRepository repository)
+{
+    public async Task<IEnumerable<Category>> GetAllAsync(CancellationToken ct = default) =>
+        await repository.GetAllAsync(ct);
+
+    public async Task<Category?> GetBySlugAsync(string slug, CancellationToken ct = default) =>
+        await repository.GetBySlugAsync(slug, ct);
+
+    public async Task<Category?> GetByIdAsync(int id, CancellationToken ct = default) =>
+        await repository.GetByIdAsync(id, ct);
+
+    public async Task<Category> CreateAsync(string name, string? description, CancellationToken ct = default)
+    {
+        var slug = GenerateSlug(name);
+        var category = new Category
+        {
+            Name = name.Trim(),
+            Slug = slug,
+            SortOrder = 0
+        };
+
+        var id = await repository.CreateAsync(category, ct);
+        return new Category { Id = id, Name = category.Name, Slug = category.Slug, SortOrder = category.SortOrder };
+    }
+
+    public async Task<Category?> UpdateAsync(int id, string name, string? description, CancellationToken ct = default)
+    {
+        var category = await repository.GetByIdAsync(id, ct);
+        if (category == null)
+            return null;
+
+        category.Name = name.Trim();
+        category.Slug = GenerateSlug(name);
+        await repository.UpdateAsync(category, ct);
+        return category;
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken ct = default) =>
+        await repository.DeleteAsync(id, ct);
+
+    private static string GenerateSlug(string name)
+    {
+        var slug = Regex.Replace(name.ToLowerInvariant(), @"[^\w\s-]", "");
+        slug = Regex.Replace(slug, @"\s+", "-");
+        slug = Regex.Replace(slug, @"-+", "-").Trim('-');
+        return slug.Length > 100 ? slug[..100] : slug;
+    }
+}
diff --git a/TaxBaik.Domain/Interfaces/ICategoryRepository.cs b/TaxBaik.Domain/Interfaces/ICategoryRepository.cs
index 4250746..9a80aba 100644
--- a/TaxBaik.Domain/Interfaces/ICategoryRepository.cs
+++ b/TaxBaik.Domain/Interfaces/ICategoryRepository.cs
@@ -6,4 +6,8 @@ public interface ICategoryRepository
 {
     Task<IEnumerable<Category>> GetAllAsync(CancellationToken cancellationToken = default);
     Task<Category?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default);
+    Task<Category?> GetByIdAsync(int id, CancellationToken cancellationToken = default);
+    Task<int> CreateAsync(Category category, CancellationToken cancellationToken = default);
+    Task UpdateAsync(Category category, CancellationToken cancellationToken = default);
+    Task DeleteAsync(int id, CancellationToken cancellationToken = default);
 }
diff --git a/TaxBaik.Infrastructure/Repositories/CategoryRepository.cs b/TaxBaik.Infrastructure/Repositories/CategoryRepository.cs
index bad0949..686b099 100644
--- a/TaxBaik.Infrastructure/Repositories/CategoryRepository.cs
+++ b/TaxBaik.Infrastructure/Repositories/CategoryRepository.cs
@@ -20,4 +20,36 @@ public class CategoryRepository(IDbConnectionFactory connectionFactory) : BaseRe
             "SELECT id, name, slug, sort_order FROM categories WHERE slug = @Slug",
             new { Slug = slug });
     }
+
+    public async Task<Category?> GetByIdAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<Category>(
+            "SELECT id, name, slug, sort_order FROM categories WHERE id = @Id",
+            new { Id = id });
+    }
+
+    public async Task<int> CreateAsync(Category category, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstAsync<int>(
+            @"INSERT INTO categories (name, slug, sort_order)
+              VALUES (@Name, @Slug, @SortOrder)
+              RETURNING id",
+            category);
+    }
+
+    public async Task UpdateAsync(Category category, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync(
+            "UPDATE categories SET name = @Name, slug = @Slug, sort_order = @SortOrder WHERE id = @Id",
+            category);
+    }
+
+    public async Task DeleteAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync("DELETE FROM categories WHERE id = @Id", new { Id = id });
+    }
 }
diff --git a/TaxBaik.Web/Controllers/AuthController.cs b/TaxBaik.Web/Controllers/AuthController.cs
new file mode 100644
index 0000000..0f98900
--- /dev/null
+++ b/TaxBaik.Web/Controllers/AuthController.cs
@@ -0,0 +1,35 @@
+using Microsoft.AspNetCore.Mvc;
+using TaxBaik.Web.Services;
+
+namespace TaxBaik.Web.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+public class AuthController : ControllerBase
+{
+    private readonly AuthService _authService;
+
+    public AuthController(AuthService authService)
+    {
+        _authService = authService;
+    }
+
+    [HttpPost("login")]
+    public async Task<IActionResult> Login([FromBody] LoginRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.Username) || string.IsNullOrWhiteSpace(request.Password))
+            return BadRequest(new { message = "Username and password are required" });
+
+        var token = await _authService.AuthenticateAndGenerateTokenAsync(request.Username, request.Password);
+        if (token == null)
+            return Unauthorized(new { message = "Invalid username or password" });
+
+        return Ok(new { token, expiresIn = 28800 });
+    }
+}
+
+public class LoginRequest
+{
+    public string Username { get; set; } = string.Empty;
+    public string Password { get; set; } = string.Empty;
+}
diff --git a/TaxBaik.Web/Controllers/BlogController.cs b/TaxBaik.Web/Controllers/BlogController.cs
new file mode 100644
index 0000000..33721af
--- /dev/null
+++ b/TaxBaik.Web/Controllers/BlogController.cs
@@ -0,0 +1,71 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using TaxBaik.Application.Services;
+using TaxBaik.Application.DTOs;
+
+namespace TaxBaik.Web.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+public class BlogController : ControllerBase
+{
+    private readonly BlogService _blogService;
+
+    public BlogController(BlogService blogService)
+    {
+        _blogService = blogService;
+    }
+
+    [HttpGet]
+    public async Task<IActionResult> GetPublished([FromQuery] int page = 1, [FromQuery] int pageSize = 12)
+    {
+        var (items, total) = await _blogService.GetPublishedPagedAsync(page, pageSize);
+        return Ok(new { data = items, total, page, pageSize });
+    }
+
+    [HttpGet("{slug}")]
+    public async Task<IActionResult> GetBySlug(string slug)
+    {
+        var post = await _blogService.GetBySlugAsync(slug);
+        if (post == null)
+            return NotFound(new { message = "Post not found" });
+        return Ok(post);
+    }
+
+    [HttpGet("admin/all")]
+    [Authorize]
+    public async Task<IActionResult> GetAll()
+    {
+        var posts = await _blogService.GetAllAsync();
+        return Ok(posts);
+    }
+
+    [HttpPost]
+    [Authorize]
+    public async Task<IActionResult> Create([FromBody] CreateBlogPostDto dto)
+    {
+        if (string.IsNullOrWhiteSpace(dto.Title) || string.IsNullOrWhiteSpace(dto.Content))
+            return BadRequest(new { message = "Title and content are required" });
+
+        var result = await _blogService.CreateAsync(dto);
+        return CreatedAtAction(nameof(GetBySlug), new { slug = result.Slug }, result);
+    }
+
+    [HttpPut("{id}")]
+    [Authorize]
+    public async Task<IActionResult> Update(int id, [FromBody] CreateBlogPostDto dto)
+    {
+        var result = await _blogService.UpdateAsync(id, dto);
+        if (result == null)
+            return NotFound(new { message = "Post not found" });
+        return Ok(result);
+    }
+
+    [HttpDelete("{id}")]
+    [Authorize]
+    public async Task<IActionResult> Delete(int id)
+    {
+        await _blogService.DeleteAsync(id);
+        return NoContent();
+    }
+}
diff --git a/TaxBaik.Web/Controllers/CategoryController.cs b/TaxBaik.Web/Controllers/CategoryController.cs
new file mode 100644
index 0000000..88c1b94
--- /dev/null
+++ b/TaxBaik.Web/Controllers/CategoryController.cs
@@ -0,0 +1,59 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using TaxBaik.Application.Services;
+
+namespace TaxBaik.Web.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+public class CategoryController : ControllerBase
+{
+    private readonly CategoryService _categoryService;
+
+    public CategoryController(CategoryService categoryService)
+    {
+        _categoryService = categoryService;
+    }
+
+    [HttpGet]
+    public async Task<IActionResult> GetAll()
+    {
+        var categories = await _categoryService.GetAllAsync();
+        return Ok(categories);
+    }
+
+    [HttpPost]
+    [Authorize]
+    public async Task<IActionResult> Create([FromBody] CreateCategoryRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.Name))
+            return BadRequest(new { message = "Category name is required" });
+
+        var category = await _categoryService.CreateAsync(request.Name, request.Description);
+        return CreatedAtAction(nameof(GetAll), category);
+    }
+
+    [HttpPut("{id}")]
+    [Authorize]
+    public async Task<IActionResult> Update(int id, [FromBody] CreateCategoryRequest request)
+    {
+        var category = await _categoryService.UpdateAsync(id, request.Name, request.Description);
+        if (category == null)
+            return NotFound(new { message = "Category not found" });
+        return Ok(category);
+    }
+
+    [HttpDelete("{id}")]
+    [Authorize]
+    public async Task<IActionResult> Delete(int id)
+    {
+        await _categoryService.DeleteAsync(id);
+        return NoContent();
+    }
+}
+
+public class CreateCategoryRequest
+{
+    public string Name { get; set; } = string.Empty;
+    public string? Description { get; set; }
+}
diff --git a/TaxBaik.Web/Controllers/InquiryController.cs b/TaxBaik.Web/Controllers/InquiryController.cs
new file mode 100644
index 0000000..0836acf
--- /dev/null
+++ b/TaxBaik.Web/Controllers/InquiryController.cs
@@ -0,0 +1,74 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using TaxBaik.Application.Services;
+using TaxBaik.Domain.Interfaces;
+
+namespace TaxBaik.Web.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+public class InquiryController : ControllerBase
+{
+    private readonly InquiryService _inquiryService;
+    private readonly IInquiryRepository _inquiryRepository;
+
+    public InquiryController(InquiryService inquiryService, IInquiryRepository inquiryRepository)
+    {
+        _inquiryService = inquiryService;
+        _inquiryRepository = inquiryRepository;
+    }
+
+    [HttpPost]
+    public async Task<IActionResult> Submit([FromBody] SubmitInquiryRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.Name) || string.IsNullOrWhiteSpace(request.Phone))
+            return BadRequest(new { message = "Name and phone are required" });
+
+        await _inquiryService.SubmitAsync(request.Name, request.Phone, request.ServiceType, request.Message);
+        return Ok(new { message = "Inquiry submitted successfully" });
+    }
+
+    [HttpGet]
+    [Authorize]
+    public async Task<IActionResult> GetPaged([FromQuery] int page = 1, [FromQuery] int pageSize = 20)
+    {
+        var (inquiries, total) = await _inquiryRepository.GetPagedAsync(page, pageSize);
+        return Ok(new { data = inquiries, total, page, pageSize });
+    }
+
+    [HttpGet("{id}")]
+    [Authorize]
+    public async Task<IActionResult> GetById(int id)
+    {
+        var inquiry = await _inquiryRepository.GetByIdAsync(id);
+        if (inquiry == null)
+            return NotFound(new { message = "Inquiry not found" });
+        return Ok(inquiry);
+    }
+
+    [HttpPut("{id}/status")]
+    [Authorize]
+    public async Task<IActionResult> UpdateStatus(int id, [FromBody] UpdateStatusRequest request)
+    {
+        var inquiry = await _inquiryRepository.GetByIdAsync(id);
+        if (inquiry == null)
+            return NotFound(new { message = "Inquiry not found" });
+
+        await _inquiryRepository.UpdateStatusAsync(id, request.Status);
+        return Ok(new { message = "Status updated" });
+    }
+}
+
+public class SubmitInquiryRequest
+{
+    public string Name { get; set; } = string.Empty;
+    public string Phone { get; set; } = string.Empty;
+    public string? Email { get; set; }
+    public string ServiceType { get; set; } = string.Empty;
+    public string Message { get; set; } = string.Empty;
+}
+
+public class UpdateStatusRequest
+{
+    public string Status { get; set; } = string.Empty;
+}
diff --git a/TaxBaik.Web/Program.cs b/TaxBaik.Web/Program.cs
index 19a2382..841f4a4 100644
--- a/TaxBaik.Web/Program.cs
+++ b/TaxBaik.Web/Program.cs
@@ -13,6 +13,9 @@ using TaxBaik.Web.Services;
 
 var builder = WebApplication.CreateBuilder(args);
 
+// Controllers (API)
+builder.Services.AddControllers();
+
 // Razor Pages + Blazor Server 통합
 builder.Services.AddRazorPages();
 builder.Services.AddRazorComponents().AddInteractiveServerComponents();
@@ -107,7 +110,8 @@ if (!app.Environment.IsDevelopment())
     app.UseHsts();
 }
 
-// Razor Pages + Blazor 매핑
+// API + Razor Pages + Blazor 매핑
+app.MapControllers();
 app.MapRazorPages();
 app.MapRazorComponents<TaxBaik.Web.Components.Admin.App>().AddInteractiveServerRenderMode();