True Offline Echo Apps on the Apple iPhone: Proof-of-Concept SDK

I finally took the plunge and picked up an iPhone a few days ago. While I was looking around for neat things that might be possible to do with it using Echo3, I ran into this page. It discusses the use of RFC 2397 (the "data" URL scheme) to embed images and even entire JavaScript/HTML applications into URLs. When you combine this with the fact that the iPhone now supports bookmarking web URLs and adding them to its "home screen", we have everything we need to create client-side Echo3 applications in JavaScript and package them up for offline iPhone use. That is, it's possible to create real Echo3 apps that can run even when the phone is out of network range or in "airplane mode".

There was one caveat: encoding URLs and applications using RFC 2397 is a horribly tedious process. My solution has been to throw together a proof-of-concept software development kit to take the pain out of it. You put in your JavaScript application and any other JS libraries you need, and out pops a ready-to-run offline Echo app for the iPhone. It can be downloaded from

New Developer Forums

Hi all,

As you may have noticed, the developer forums have now been fully integrated into the web site. Please take note of the following:

2.1rc3 Incorrect Release Issue Fixed: Re-download Now.

Prior to January 23, 2008 at 00:30 UTC, the download link for 2.1.rc3 was in fact providing an older release. If you downloaded Echo2 2.1rc3 before this time, please re-download a new version immediately. While this problem did not affect all downloads, we highly recommend that you download a new version now to be certain you have the correct item.

You can verify that you have the correct version by one of two methods:

  • Verify the file "/SourceCode/src/app/java/nextapp/echo2/app/" contains the text "2.1.rc3".
  • In a browser, view the source of an Echo application compiled with your 2.1rc3 and be certain it contains the text "2.1.rc3".

Echo 2.1rc3, Extras 0.9 Released

A new, long-awaited release candidate of Echo2 is now available. This is mostly a bugfix release, is now nearly devoid of Echo2 bugs, please get them in soon if you want them fixed for 2.1 final. Downloads are available here:

A new release of Extras is also available, version 0.9. Downloads are available here:

A new EchoStudio build will be available soon, though there are a couple bugfixes in the queue before this one drops.

Now witness the firepower of this fully armed and operational battle station!

Good morning all,

The Echo project has now officially moved to its new home at All open-source material from has been moved here. Commercial products, i.e., EchoStudio, and corporate information remain on the old site.

The new site is markedly easier to maintain and update than the previous item. Changes can be made in place very quickly--if you catch it at the right time, for example, you may see documentation actually being written. The overall mood here is intended to be less formal than on the old site. For example, you're free to post comments to articles such as this one.

Echo3 New Features

The following provides an overview of some major new features present in Echo3 (compared to Echo2). This list is not yet complete.

Server-Side Java Features

  • Component Framework Backward Compatibility: The Echo3 and Echo3Extras Java libraries are MOSTLY backward compatible with Echo2. Some porting work is required: the most notable issue is that the base package name has been changed form "nextapp.echo2" to "nextapp.echo". The first step in porting is thus a global search-and-replace. XML Stylesheets must be translated to a new format (a translator is provided). Additionally, EchoStudio3 provides a complete project translation utility. The only significant work in porting is with custom components which render their own HTML and JavaScript: such components must be ported to a new API (which is far more straightforward and automated than the Echo2 equivalent). is Online

Hello all,

This site is the new home of the Echo web framework. will continue on as the corporate site for NextApp, but all Echo content will be moved here. This site is being built using Drupal, an open-source content management platform. It is substantially easier to develop and manipulate content here than attempting to build manually with HTML code. This site additionally opens up new features such as the ability to create blogs such as this one.

I'd greatly appreciate any feedback about the new site and any suggestions to improve it. At this time though the site is under heavy development. Please continue to check the Echo resources at when you find content to be missing here.


Quick Echo3 Status Update everyone has probably figured out by now, yes, it's going to be called Echo3.

There are currently several developers working full time on v3 (core and extras), myself included. Full time is a relative term, of course, I'm doing other things but do tend to be spending in excess of 40hr/week on 3.

As for the status of 3... it compiles. It runs. Performance and stability are looking good. The new web container concept is solid. Extras components are being implemented at a good rate, and there are some big improvements on that side.

2.1 Release Candidate

A release candidate version of the Echo 2.1 platform is now available for download. Please report any issues on the developer forums.

Comparing the Google Web Toolkit to Echo2

Originally posted @

The Google Web Toolkit (GWT) is being compared to Echo2 quite frequently. Some of these comparisons have been fairly accurate, while others contain bits of misinformation. This article, written by the lead developer of Echo2, discusses the similarities and differences between these two frameworks.

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