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CheerpX for Flash now generally available

A pure HTML5 solution to extend the life of Flash applications on any browser

Adobe Flash Player check page running with CheerpX for Flash.

Today we announce the general availability of CheerpX for Flash, a solution for organisations to extend the life of existing Flash applications on any browser after December 2020.

CheerpX for Flash allows organisations to extend the life of any Flash-based application, including Flex, Spark and OpenLaszlo applications. Applications built using any framework, with any build environment, are compatible with CheerpX for Flash.

This solution primarily targets the Enterprise sector, in urgent need to extend the life of complex existing Flash applications, particularly those based on Flex, and those that face customers or the general public. It requires only a minimal intervention to the application HTTP server and has no requirement on the end-user (i.e. no custom browser or extension).

How does CheerpX for Flash work?

Further information about the internals of CheerpX for Flash can be found on previous blog posts (here and here), as well as on our website.

CheerpX for Flash is based on two main components:

  1. The Adobe Flash Player, together with its full runtime environment;
  2. The CheerpX virtual machine, an HTML5 ‘emulator’ that can run the Adobe Flash Player

CheerpX, a technology still unreleased to the public, is an HTML5 (WebAssembly) solution to run Linux binaries in-browser, client-side. It is essentially an HTML5 virtual machine, with an operating-system emulation layer. It can run binaries very efficiently via a unique x86 to WebAssembly JIT engine. More detail on CheerpX is available on our website and in previous posts in our technical blog.

By combining CheerpX with the Adobe Flash Player, CheerpX for Flash creates a virtual environment that is equivalent to running the regular Flash Player with its runtime, except in an HTML5 compliant way. This means that any Flash application that runs on the Adobe Flash Player (all of them) can run in principle with CheerpX for Flash.

By adding CheerpX for Flash to any Flash page, the page is ‘transformed’ to HTML5, making it compatible with any browser without the Flash Player. CheerpX for Flash is a pure HTML5 solution, made of JavaScript, WebAssembly and HTML/CSS, that does not require any back-end other than an HTTP server.

How do I integrate CheerpX for Flash?

CheerpX for Flash is easily integrated on any existing HTML page that embeds Flash via the <embed>, <object> tags or swfobject.js library.

Basic integration of CheerpX for Flash on an existing HTML/Flash page.

CheerpX for Flash is a collection of static assets (HTML, JavaScript, WebAssembly and CSS) that can be hosted on any HTTP server, including CDNs.

All of CheerpX for Flash assets are cacheable, and amount to a total download size of ~7 MB. Any number of HTML pages with Flash can point to the same CheerpX for Flash installation.

An alternative integration method via a custom extension for Chrome and Microsoft Edge will be available for any organisation without direct control over the back-end, or whenever modifying the source .html files is inconvenient.

Deployment of CheerpX for Flash

CheerpX is available as either cloud software, hosted by Leaning Technologies, or for self-hosting.

The cloud version of CheerpX for Flash can be used by applications where the end-users are exposed to the internet.

It is backed by an enterprise-grade worldwide CDN for minimal latency, high download speed and uptime guarantees. No limitations to bandwidth and no logging whatsoever are enforced. This deployment is currently used by our Java product CheerpJ for many years, and supports over 800,000 unique monthly users, serving about 20TB of data each month.

CheerpX for Flash is also available for self-hosting on public and private clouds, as well as on private networks, air-gapped environments, and on-premise installations.

The requirements for self-hosting are minimal. CheerpX for Flash is compatible with virtually any HTTP server. There is no active backend component to CheerpX.

Early Adopters

Since January 2020, we have been working with a few dozen early adopters, including Fortune 100 and NASDAQ companies, large European corporations, as well as public sector, non-governmental and not-for-profit organisations.

Early Adopters of CheerpX for Flash have been interested in its application to customer- and public-facing applications, as well as for internal applications. In a few cases, CheerpX for Flash is being explored as an option to run third-party, self-hosted Flash applications.


CheerpX for Flash is an Enterprise solution for the preservation of existing Flash applications, based on the Adobe Flash Player.

Licences for CheerpX for Flash are organisation-wide, with flat yearly pricing irrespective of the number of users, applications, or the number of requests made (in the case of cloud deployment).

To use CheerpX for Flash, a licence is required for both CheerpX itself, and for distributing the Adobe Flash Player. This is a requirement for both self-hosted and cloud-hosted installations. In many cases, we will be able to offer both licences under the same commercial agreement. In some cases, a separate licence will need to be procured from Harman. Leaning Technologies can make the right introductions and facilitate the conversation with Harman.

Not-for-profit, charitable and educational organisations can benefit from discounted rates.

An exclusive partnership has been negotiated with a leading HTML5 game distribution platform, which will make CheerpX for Flash available to any video game publisher, distributor, and creator. A dedicated announcement will be made by our partner in due course.


An Enterprise Evaluation Programme is available for organisations interested in exploring CheerpX for Flash with the assistance of our technical team. If you would like to find out more about our Enterprise Evaluation Programme, please get in touch with sales@leaningtech.com.

For Partners

We are welcoming new partnerships with IT, Consultancy and third-party support firms to join our Partner Program for exclusive support to our line of bespoke tools to extend the life of legacy Flash & Java applications and our specialist expertise in WebAssembly.

If you would like to find out more about our Partner Program, please get in touch with sales@leaningtech.com.



Leaning Technologies' Blog - everything WebVM, Cheerp, CheerpJ, CheerpX, compile-to-WebAssembly and WebAssembly virtualization

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