ASP.NET Web Forms upload control · v5.0

Modern file uploads for Web Forms.

Drop-in server control that adds drag and drop, multi-file queues, chunked uploads, image previews, and client-side validation to any ASP.NET Web Forms page. Ships with 101 working demos.

Explore 101 Demos Download Package No license needed for localhost

15,000+

Licensed teams worldwide

20+

Years in production

101

Ready-to-run demos included

AjaxUploader Demo

Single file upload

Drop zone

Custom queue

Real screenshots from the 101 demos shipped with AjaxUploader 5.0.

Core capabilities

Everything you need for production file uploads.

A complete upload toolkit — not just a file input replacement. One server control handles the hard parts so you can focus on your application.

Multiple file selection

Users pick many files at once from the file dialog. No more one-at-a-time uploads or page refreshes between selections.

Drag and drop

Styled drop zones with hover feedback. Users drag files or entire folders straight from their desktop onto the page.

Chunked uploads

Large files are split into chunks with automatic retries and progress tracking. Survives flaky connections and IIS request limits.

Client-side validation

Reject wrong file types, oversized files, and invalid dimensions before anything hits the server. Custom rules supported.

Image previews

Instant thumbnail previews, gallery layouts, and avatar cropping workflows — all client-side before the upload starts.

CuteWebUI 4.x upgrade path

v5 includes the CuteWebUI compatibility layer. Existing pages keep compiling while you migrate to the new API at your own pace.

See all features →

Quick start

Drop the server control onto a page

<%@ Register Assembly="AjaxUploader" Namespace="AjaxUploader.Controls" TagPrefix="au" %>

<au:AjaxFileUpload ID="Uploader1" runat="server"
    AllowMultiple="true"
    AllowedExtensions=".jpg,.png,.gif,.pdf,.docx"
    MaxFileSize="5MB"
    AutoUpload="true"
    ShowProgress="true"
    EnableDropZone="true" />

Evaluate locally

No license key needed for development.

Download the package, open in Visual Studio, and start testing immediately. All 101 demos run on localhost without a license. You only need a license file when you deploy to a production domain.

Download package

ASP.NET Core?

Use CoreUpload for the Core stack.

AjaxUploader is the Web Forms edition. For ASP.NET Core apps, CoreUpload provides middleware and Tag Helper integration.

Visit CoreUpload →

What's new in v5

A ground-up rewrite for modern browsers.

Version 5 replaces the legacy Flash and Silverlight transport with a pure JavaScript engine built on the Fetch API and modern drag-and-drop. The result is a smaller footprint, faster uploads, and zero browser plugin dependencies.

Upgrade guide Full feature list

Pure JS

No Flash, no Silverlight, no Java applet. Works in every modern browser out of the box.

Fetch API

Built on the Fetch API with chunked transfer, progress events, and automatic retries.

101 Demos

Every feature has a running demo you can open in Visual Studio and adapt to your project.

4.x Compat

CuteWebUI namespace shims let existing pages compile unchanged during migration.

Download package

Everything to evaluate, deploy, or upgrade.

The package includes Web Forms binaries, 101 working demos, class reference documentation, deployment notes, and upgrade guidance for older 4.x projects.

Download package Documentation

Runtime

Embedded assets

JS and CSS are embedded in AjaxUploader.dll and served through ajaxupload.axd.

Demos

101 working demos

Open a ready-to-run sample project instead of reconstructing features from isolated code snippets.

Compatibility

4.x migration

Keep older CuteWebUI pages compiling while moving toward native v5 controls at your own pace.

Licensing

Friction-free dev

Localhost bypasses license detection. Install ajaxuploader5.lic for production.

Uploader family

Choose the uploader for your stack.

ASP.NET Core