If you are working on a project that requires creating an endpoint for uploading an image or file, then you have come to the right place. In this blog post, we will discuss how to write an ASP.NET Core API endpoint for uploading an image. 
To create an ASP.NET Core API endpoint for uploading an image, you can follow these steps. 
1.Create a Model: Define a model that represents the data structure for your API. In this case, you might need a model to handle the image upload.
// ImageUploadModel.cs
public class ImageUploadModel
    public IFormFile Image { get; set; }
2.Update Startup.cs: In your Startup.cs file, configure services to enable file uploads and configure CORS if needed.
public void ConfigureServices(IServiceCollection services)
    // Other service configurations


    // Enable multipart/form-data for file uploads
    services.AddMvc(options =>
        options.EnableEndpointRouting = false;
        options.Filters.Add(new ConsumesAttribute("multipart/form-data"));

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    // Other app configurations

    // Enable CORS if needed
    app.UseCors(builder =>

    // Enable static files for testing (you might skip this in production)

    // Enable MVC
3.Create the Controller: Create a controller with an action to handle the image upload.
// ImageController.cs
public class ImageController : ControllerBase
    public async Task<IActionResult> Upload([FromForm] ImageUploadModel model)
            if (model.Image != null && model.Image.Length > 0)
                // Process the uploaded image here (e.g., save to disk or database)
                // For simplicity, this example saves the file to wwwroot/uploads
                var uploadsFolder = Path.Combine(Directory.GetCurrentDirectory(), "wwwroot", "uploads");
                var filePath = Path.Combine(uploadsFolder, model.Image.FileName);

                using (var fileStream = new FileStream(filePath, FileMode.Create))
                    await model.Image.CopyToAsync(fileStream);

                return Ok(new { Message = "Image uploaded successfully" });
                return BadRequest("No image file specified.");
        catch (Exception ex)
            return StatusCode(500, $"Internal server error: {ex.Message}");
This controller action receives an ImageUploadModel as a parameter, which includes a property Image of type IFormFile. The action then processes the uploaded image. In this example, it saves the image to a folder named "uploads" within the "wwwroot" directory. 
4.Testing the API: You can test the API using tools like Postman or by creating a simple HTML form. Ensure that the form has the enctype="multipart/form-data" attribute for handling file uploads.
<!-- index.html -->
<form action="https://api-url/api/image/upload" method="post" enctype="multipart/form-data">
    <input type="file" name="image" />
    <button type="submit">Upload Image</button>
Remember to handle security considerations appropriately, especially if this API will be used in a production environment. 
This includes validating and sanitizing user input, setting up proper authentication, and handling authorization as needed.