INTRODUCTION TO OPEN WEB APPS

Open Web Apps are essentially no different than standard websites or Web pages. They are built using standard open Web technologies — HTML, CSS, JavaScript, etc. — and can be accessed using a Web browser. The main differences lie in their ability to be installed on a device and work offline, and access to advanced APIs that allow interaction with device features such as the camera, address book, and other such things. In addition, they are built on open technologies as much as is possible. 

Advantages of Open Web Apps

Local installation and offline storage:  Open Web Apps can be installed on the device, and leverage APIs such as local storage and IndexedDB to provide local data storage capabilities. In addition, open Web technologies tend to have a much smaller footprint than native apps and can generally be updated atomically rather than having to install a complete new package each time there's an update. (An exception to this is packages apps, which require a whole new package when updating.) Apps are therefore less dependent on an always-on Web connection and more useful when networks are patchy.

      Hardware access: The metadata provided with Open Web Apps can be used to grant the application permission to privileged APIs that enable usage of device hardware features, something the Web platform has not traditionally enjoyed.

Breaking the walled gardens: The norm for mobile platforms tends to be walled gardens written with proprietary technologies, so apps are locked inside their platforms. And smartphone tend to be expensive, and require credit cards for app purchases. Open Web Apps tend to be able to run on much cheaper hardware, especially in the case of Firefox OS devices where you've literally just got Firefox running on top of a lightweight Linux kernel. And they are written using open Web technologies, which is the most distributed platform around. In addition, Firefox OS devices feature payment systems where you can simply prepay for apps, or add the cost to your phone bill.

Open Web App stores: Following on from the previous point, you can choose to host your apps in an existing marketplace (such as the Firefox Marketplace), or host them somewhere else entirely. It's up to you. Mozilla aims to put the developer back in control of every aspect of the app experience — from easy development to distribution to direct customer relationship management. And the apps can be searched for just like any other Web-based experience.

The Web is platform

An open web app as it exists as installed on a platform like Firefox OS is not a bookmark — it’s a proper part of the system. Open Web Apps hold that great promise. They are an opportunity that we should not miss; otherwise the Web might become fragmented once more. With this in mind it should be made clear that Open Web Apps (OWA in short) are intended to be standardized and to become part of "the Web". If successful, OWA should eventually work on all browsers, operating systems and devices.

At Mozilla we are working hard to create this apps platform that is backed entirely by the open Web. It’s not intended to be a “Mozilla platform” or a “Firefox platform”. The Web is the platform. We’re creating a set of open APIs and implementations to show how portable apps can exist on the Web without vendor lock-in. Other groups like Face book and Google Chrome are also working on apps platforms backed by the Web. Face book apps are meant to hook into Face book and Chrome apps are designed for Chrome OS devices and Google servers. Chrome apps are the most similar to Open Web Apps. We continue to collaborate with the Google Chrome team as app standards evolve and we definitely share a lot of the same vision. There is tremendous potential for all Web based app platforms to converge and we invite all vendors to help us build the right Open Web App APIs.

Even though currently you must have a Mozilla Firefox-based engine ("Web runtime") to use Open Web Apps, it is not intended that this always will be the case. Many parts of the Open Web Apps project are still being worked out and it isn't possible to implement everything in all browsers at once. Although many parts of Open Web Apps are already standardized, many other parts are still in flux. It is intended and hoped that Open Web Apps will be a standard capability that is available in all major browsers.

App Tools

App validator

Is your app ready for the Firefox Marketplace? The App validator will check your manifest and show you any errors it may have, or warnings you should consider.

Firefox OS simulator

Installing and using the Firefox OS Simulator is the easiest way to get up and running with your app. After installed the simulator is accessible via the Tools -> Web Developer -> Firefox OS Simulator menu. The simulator launches with a JavaScript console so that you may debug your application from within the simulator!

App manager

The new kid on the block with regards to testing tools is called the App Manager. This tool allows you to connect desktop Firefox to a compatible device via USB (or a Firefox OS simulator), push apps straight to the device, validate apps, and debug them as they run on the device.

Firefox developer tools

Firefox now ships with a default set of developer tools built from the ground up to ensure a great development experience that is both snappy and efficient. To find out more about how these tools work, and see a detailed list of what else Mozilla has to offer, head on over to our Tools zone.

App publishing options

The Firefox Marketplace is our own dedicated app store for distributing free and paid apps. Submitting an app to the Firefox Marketplace is a simple process, involving uploading the app itself plus surrounding information, and waiting for it to go through our thorough review process to make sure it is high quality and not malicious. Submitting to the Firefox Marketplace also confers other advantages such as increased publicity, no need to implement special APIs on your own web site, and the possibility of publishing paid apps more easily. You can submit both hosted apps and packaged apps to the Firefox Marketplace.

Hosted apps

A hosted app is basically an app hosted on a web server just like a regular web page. If you want to let people install a hosted app straight from the site, you must implement some JavaScript code on your Web site to manage installing and updating your app into users' browsers, and make sure your app code includes a valid manifest file. Please see our write-ups of manifest files and Install API functionality for how simple these steps are to implement.

Where you host the app is really up to you, but the two options listed below are probably the most common and easiest

GitHub - If the Web app is purely static (HTML/CSS/JavaScript, but no server-side processing), GitHub Pages is a solid hosting option. It will serve your manifest with the correct MIME type if you give it a .webapp extension.

Generic hosting solutions - For dynamic websites, use a generic hosting option (like a Web server you may already own or have access to) with the right capabilities or a hosting provider specifically tailored to the needs of your app, like Heroku or Google App Engine.

Packaged apps

A packaged app is an Open Web App that has all of its resources (HTML, CSS, JavaScript, app manifest and so on) contained in a zip file, instead of having its resources on a Web server. A packaged app is simply a zip file with the app manifest in its root directory. The manifest must be named manifest.webapp. One difference from a hosted app is that a packaged app must specify a launch_path in the manifest, whereas it's an optional manifest field for a hosted app.

Self publishing apps

You can also choose to self-publish apps. For hosted apps, this just involves putting them up on web hosting, as detailed above. You can self-publish a packaged app by hosting it on a server along with a mini-manifest in the same directory that identifies the app and is used in the install process.