Cross-Browser Extensions API?

Question

There are tools for developing cross-platform browser plugins.

Are there any similar tools or APIs for browser extensions (i.e. toolbars, or filter systems like AdBlock)?

Solution 1

Yes, but unfortunately each one has significant drawbacks.

• Kynetx supports IE, Firefox, Safari, and Chrome, but extensions are dependent on the Kynetx extension to work. In addition, Kynetx apps are built using an odd, proprietary Kynetx Rules Language. There is no cost to use the Kynetx platform. UPDATE: Kynetx has shut down

• WebMynd supports IE, Firefox, Safari, Chrome, and is in private beta. From what I have been able to determine, WebMynd is a very small San Francisco-based startup that is still getting off the ground. Their library is standalone and provides a Javascript API, and they use a monthly billing model. UPDATE: company pivoted, now for mobile, trigger.io

• Crossrider supports IE, Firefox, Chrome and Safari. Recently out of beta (as of June 2012), Crossrider is free and offers a jQuery-based development experience. Publishing methods for your extensions include an embeddable website widget, download links, and a customized windows installer. However, CrossRider does not allow you to self-host your plugin files. UPDATE: As of 27.09.2016, CrossRider is terminated and it will be available only until 27.10.2016.

• KangoExtensions supports IE, Firefox, Chrome, Safari, Opera. Seems very new and bleeding edge, like Crossrider, also looks promising. UPDATE: No updates in over two years.

IE and Firefox seem to be the hardest to develop for, although Mozilla JetPack aims to greatly simplify Firefox extension development.

Solution 2

There is also very young framework for cross-browser development called BabelExt, from the author of Reddit Enhancement Suite. I like that it builds restartless Jetpacks for Firefox.

See more on github, https://github.com/honestbleeps/BabelExt

Solution 3

Mozilla has recently introduced WebExtensions API. For now it's actually almost a copy of Chrome Extension API (but some APIs aren't implemented yet). It has been introduced just a few days ago so it still has a lot of problems and unsupported APIs. But if you're interested in writing extensions for Chrome, Opera and Firefox you should pay attention to the state of WebExtensions API.

UPD 27.10.16. There is a page Are-we-WebExtensions-Yet which summarises the current state of WebExtensions. By their current estimate 44.99% extensions from Chrome store should work in Firefox.

Comments

[shdev]

Great post Jonathan. One little comment regarding Crossrider. Crossrider is a white-label framework and as such, extensions can be downloaded from your own site. Crossrider provides an embed widget that detects the user's browsers and download their platform's exntesion file. You can also use the direct download links to .crx .xpi and .exe files (chrome/ff/ie). You can also serve those extension files from your own servers. One last note: Safari support is coming soon.

[Amir Nathoo]

Thanks for the mention of WebMynd. We've now launched in public beta with tutorial and API documentation here: docs.webmynd.com/en/latest/index.html

[the_void]

KangoExtensions is an option only if you're open-source or willing to spend a couple of thousand $$

[Paul Carlton]

What are the drawbacks of CrossRider?

[Jonathon Hill]

The drawbacks of Crossrider appear to be less than when I originally wrote the post, and they are worth a try. Their main drawback at this point is that they are a proprietary layer of technology in your application, which would cause problems if you need to be able to dynamically compile extension packages (as my application required), or if the company should go belly-up (they are a startup, after all). I would be more comfortable if they provided their libraries and compilation tools open source.

[Shane Holloway]

Great find Tim — it is a great example of building extensions from scratch as well!

[Delicia Brummitt]

It appears that WebMynd has done a pivot, and is now focusing on Cross-platform Mobile Development with PhoneGap, Sencha, and Appcelerator as their competitors.

[Michal Stefanow]

I wonder what is the current state? quora.com/… Is there a single, reliable, supported platform with community etc...?

[enguerranws]

About Kango, they only provide Chrome / Safari / FF support on "free" version, for IE support, you must pay $2290 (just asked).

[riot_starter]

WebExtensions are now supported by Opera and Edge too (by a varying degree).

[Mario Pérez Alarcón]

Update: "BabelExt is essentially obsolete at this point, as Firefox now supports WebExtensions, Opera is now Chromium-based, and even Microsoft Edge has adopted Chrome's format."

[sampathsris]

This answer is probably getting obsolete as the WebExtensions API is gaining popularity and acceptance. If you have an idea for an extension, it should most probably be written in WebExtensions API.

[Eric Martindale]

I've used Kango in the past, but as of 2021 it appears all download links and source code have been disabled/deleted. Perhaps a security compromise?