AjaxUploader 5.1 ASP.NET Core edition

File uploads for ASP.NET Web Forms that can handle real production traffic.

Add resumable uploads, direct-to-cloud transfers, drag and drop, image handling, validation, progress UI, and legacy 4.x compatibility without rebuilding your upload pipeline from scratch.

Explore 119 demos Download package

15k+ licensed teams

20+ years shipping

7 upload strategies

Drop zone with resumable chunks

Current file design-system-assets.zip

74% uploaded - 4 parallel chunks

Strategy Direct to S3 Signed by Web Forms, bytes bypass IIS

Built for old and new systems

Modern upload workflows, still comfortable inside Web Forms.

AjaxUploader keeps the server-control ergonomics teams know, while adding the transport, resume, security, and UI features expected from a current upload platform.

Pluggable strategies

Switch between single POST, chunked, tus, URL import, S3, Azure Blob, and Google Cloud Storage from one control property.

Direct-to-cloud

Let the browser stream large files straight to cloud storage using server-generated signatures and your existing provider flow.

Resumable uploads

IndexedDB persistence keeps chunk offsets, tus sessions, and S3 part data available after reloads and tab crashes.

Validation and security

Client and server checks for extensions, MIME type, size, duplicate detection, dimensions, custom rules, and scan hooks.

Image workflows

Preview, resize, crop, rotate, compress, annotate, auto-orient, and convert HEIC before the upload starts.

Global-ready UI

Thirty built-in locales, RTL support, smooth progress states, keyboard-friendly controls, and custom UI events.

See it working

The demo suite is the documentation you can run.

Use ready-made samples for basic uploads, validation, drag and drop, progress UI, queueing, image handling, security, integrations, and v5 cloud features.

Browse demos Read docs

AjaxUploader single file upload demo — Single file upload

AjaxUploader queue upload demo — Custom queue

AjaxUploader drop zone demo — Drop zones

Quick start

Drop one server control onto a page and configure the upload path.

Use declarative markup for the common cases, then wire server events and client callbacks when you need deeper control.

Localhost runs without a license key Embedded JS and CSS served by ajaxupload.axd 4.x compatibility namespace included

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

<au:AjaxFileUpload ID="Uploader1" runat="server"
  AllowMultiple="true"
  EnableDropZone="true"
  Strategy="chunked"
  ChunkConcurrency="4"
  PersistState="true"
  MaxFileSize="500MB" />

One upload core

Pick the product that matches your stack.

The Web Forms control shares its JavaScript upload engine with the broader uploader family.

Web Forms

AjaxUploader

Server controls, Visual Studio-friendly demos, and compatibility for long-lived ASP.NET applications.

ASP.NET Core

CoreUpload

Razor Pages, minimal APIs, and modern .NET application patterns.

JavaScript

MultipleUpload

Standalone frontend package for any backend or framework.

Evaluate today

Download the full package and test every scenario locally.

Includes binaries, docs, migration notes, API reference, deployment notes, and working demos.

Download AjaxUploader