The latest release of JetPack brings two new APIs in the fold; the Toolbar API, which lets JetPack developers place custom buttons and controls in the Firefox UI much like traditional add-ons can do, and a new Places API, which allows JetPack add-ons to interact with Firefox’s history and bookmarking tools.
Together with the existing APIs, JetPack is starting to look like a much more capable platform for add-ons developers. While JetPack will never be able to duplicate all the functionality of the existing Firefox add-ons system, Mozilla’s plan is migrate as many developers and add-ons as possible to JetPack without eliminating the existing platform.
Eventually, Mozilla plans to incorporate JetPack into Firefox release, most likely Firefox 4.0, due at the end of next year, though there is some chance JetPack could be part of the planned upgrades between now and then. For now though, interested developers can grab the JetPack add-on that allows JetPack to work within current version of Firefox.
While JetPack was innovative when Mozilla first announced it, Google has since added an extension system to its Chrome browser that works on the same principles as JetPack — using web-based tools like HTML and CSS. It would be nice if Chrome extensions would work with JetPack and vice versa, but differences between the underlying browsers make such compatibility unlikely.
Jetpack is still an experimental Labs project and may have some bugs, but if you’d like to take some JetPacks for a spin, head over to the Labs website, install the add-on and then browse the available JetPack extensions.