AutoAuth, Comment Snob, Feed Sidebar, Links Like This, Mozilla, Mozilla Add-ons, Mozilla Firefox, OPML Support, RSS Ticker, YouTube Comment Snob

My Future of Developing Firefox Add-ons

Note: AutoAuth is now being developed by Steffan Schlein. If you would like to leave feedback, pleaseĀ create an issue on GitHub.

Mozilla announced today that add-ons that depend on XUL, XPCOM, or XBL will be deprecated and subsequently incompatible with future versions of Firefox:

Consequently, we have decided to deprecate add-ons that depend on XUL, XPCOM, and XBL. We don’t have a specific timeline for deprecation, but most likely it will take place within 12 to 18 months from now. We are announcing the change now so that developers can prepare and offer feedback.

In response to this announcement, I’ve taken the step of discontinuing all of my Firefox add-ons. They all depend on XUL or XPCOM, so there’s no sense in developing them for the next year only to see them become non-functional. AutoAuth, Comment Snob, Feed Sidebar, Links Like This, OPML Support, RSS Ticker, and Tab History Redux should be considered unsupported as of now. (If for any reason, you’d like to take over development of any of them, e-mail me.)

While I don’t like Mozilla’s decision (and I don’t think it’s the best thing for the future of Firefox), I understand it; there’s a lot of innovation that could happen in Web browser technology that is stifled because of a decade-old add-on model. I only hope that the strides a lighter-weight Firefox can make will outweigh the loss of the thousands of add-ons that made it as popular as it is today.

Browser Add-ons, Feed Sidebar, For Sale, Mozilla, Mozilla Add-ons, Mozilla Firefox, RSS Ticker

Firefox Add-ons for Sale

The time has come for two add-ons, RSS Ticker and Feed Sidebar, to find new owners.

Since I started developing add-ons for Firefox, I’ve written at least forty different extensions: some for personal use, some as a freelancer, and some as the primary function of my full-time employment.

In order to free up more time to pursue new ideas and projects, I occasionally need to either retire or transfer ownership of add-ons that I wrote of my own volition. Some of these, like TwitterBar and FireFound, were retired by executive decision. Today marks the first time that I am attempting to actively sell the rights to some of my add-ons.

Allow me to brag about these add-ons

RSS Ticker and Feed Sidebar are my two most popular add-ons, and they’re fully functional in the most recent version of Firefox.

RSS Ticker Screenshot

Both of them have been featured as “featured” or “recommended” add-ons Mozilla Add-ons multiple times, and both maintain healthy usage by a dedicated base of users not interested in Web-based feed readers.

RSS Ticker averages 39,000 daily users and has been download 1.3 million times. Feed Sidebar averages 21,000 daily users and has been download over 900,000 times. The two add-ons are unlikely to have overlapping users.

RSS Ticker is the first Google result for firefox ticker. It is also the first result for rss ticker and feed ticker.

Feed Sidebar screenshot

Feed Sidebar is the fourth result for firefox feeds and firefox feed reader and number two for firefox feed. It’s number one for feed sidebar.

Both of these add-ons would be excellent footholds for a Web-based feed reader to attract users who prefer to consume news directly from their browsers; they would be equally beneficial for content-oriented sites to push recommended feeds to users via the already-integrated “Featured Feeds” feature in both add-ons. (Both extensions regularly check a list of “Featured Feeds” and suggest these feeds as subscriptions to their users.)

What do you get if you buy?

If you buy either of these add-ons, I’ll:

  1. Transfer ownership of the add-on(s) to you on Mozilla Add-ons.
  2. Redirect the add-on pages on my blog to the pages of your choosing.
  3. Forward any feedback e-mail I receive regarding the add-ons indefinitely.
  4. Add you to my Christmas card list.
  5. Be a good guy in general and offer free consulting and advice related to the add-on(s) for as long as I can.

If you’re interested in purchasing either or both of these add-ons and taking over their development, e-mail me at

Browser Add-ons, Flock, Mozilla, Mozilla Add-ons, Mozilla Firefox, Mozilla Firefox for Mobile, Netscape Navigator, Software, URL Fixer

URL Fixer Has Been Acquired

Update: URL Fixer was acquired and is now hosted at

URL Fixer, one of the first add-ons I wrote for Firefox, has been acquired! It is now being managed by the team at

URL Fixer was inspired in 2006 by this Firefox bug report. Since then, it has been a featured add-on on the Mozilla Add-ons Gallery, it was one of the first add-ons to be compatible with Mobile Firefox, and it placed in the Extend Firefox 2 contest. It used to be compatible with both SeaMonkey and Flock (remember Flock?); its functionality was included in Netscape Navigator 9, and it was at one point under consideration to be included in Firefox 3.

URL Fixer has also been the subject of several experiments: it was the source of the statistics I used in my examination of what people type in the address bar, and it was the add-on I used to test the feasibility of selling a freemium browser add-on.

The new team in charge of URL Fixer recently released version 4, which you can install without needing to restart Firefox; I’m looking forward to seeing what other improvements they make and in what direction they take the add-on. Please note: support questions should no longer go to me; please send them to

Browser Add-ons, Mozilla, Mozilla Add-ons, Mozilla Firefox, Slashdot, Slashdotter

Discontinuing Slashdotter

Slashdotter is an extension I wrote in 2006 in order to customize the Slashdot experience. It was covered on Slashdot and was received favorably by the Slashdot audience, but I don’t have the time anymore to update it every time Slashdot changes their UI or HTML.

If you’d like to take over development, let me know, and I’ll transfer the Slashdotter add-on to you on AMO; if nobody volunteers, I’ll be removing the add-on from AMO in a couple of weeks. (Like all of my browser extensions, Slashdotter’s source code is open source, so you could still develop your own version if you want.)

Browser Add-ons, Mozilla, Mozilla Add-ons, Mozilla Fennec, Mozilla Firefox for Mobile, Programming, Tapsure

Tapsure: Better password input on mobile devices

Typing passwords on mobile devices sucks. If you have even a reasonably strong password (one that includes letters, numbers, and special characters), it can take more than a few seconds to type it out on a phone’s keypad or on-screen keyboard. In this day and age, that’s time you just don’t have!

Tapsure is an extension for Firefox for Mobile that alleviates this problem by allowing you to input passwords on websites by tapping a rhythm on your touchscreen rather than hunting through the device’s keyboard.

How does it work?

Install Tapsure here, and after restarting Firefox for Mobile, log into one of your online accounts as usual. After you log in, you’ll see a notification from Tapsure:

Choose “Yes,” and you’ll see this dialog:

(If you choose “No,” Tapsure will never ask about that specific password again. If you just close the notification, Tapsure will ask the next time you use the password.)

Here comes the fun part: think of a song, a pattern, a rhythm, or even some Morse code that you want to use to log in to sites that use this password – it can be anything, as long as it doesn’t have more than a full second between taps. Got it? Ok, now tap that song/pattern/rhythm/Morse code on the screen. Tapsure will save it and close the dialog.

Now, the next time you’re logging into a site that uses that password, instead of slowly typing out your super-secure 20-character password, just hold your finger down on the password field until you see this:

Now tap out your pattern from the previous step, and Tapsure will automatically fill in your password for you. (If you tap the pattern incorrectly, Tapsure will shake it off and give you another chance.)

You can repeat these steps for as many passwords as you like – Tapsure will remember them all.

Tapsure Settings

In the add-on options panel, you can reset all of the patterns you’ve saved with Tapsure to start over. (This will also clear the list of passwords that Tapsure won’t ask you to save a pattern for.)

Is this secure?

Yes, Tapsure saves your patterns and passwords using Firefox’s built-in password manager, so it just as secure as having Firefox remember your passwords. Tapsure also has the benefit that someone could closely watch you log in to a website without knowing your password, because it’s harder to discern and remember a tapped pattern than it is to watch the keys that you press.

Couldn’t I just tell Firefox to remember the password?

You could… but if you use the same password on more than one site (which I estimate that 99.9% of people do), you’d have to type it out with excruciating care on every single site that you use it on.


Try and use a semi-unique pattern – don’t choose Happy Birthday. It’s like using the password “password.”

Tapsure probably works better on capacitive touchscreens than resistive touch screens, simply due to the fact that it’s easier to tap a quick pattern when you don’t have to press down firmly on each tap.

Tapsure was entered in the Firefox Mobile Add-ons Cup. If you want to see it win, please write to your senators and representatives.

Where can I install it again?

Or, you can search for “Tapsure” in the “Get Add-ons” portion of Firefox for Mobile.

Browser Add-ons, Fat Plug, Mozilla, Mozilla Add-ons, Mozilla Firefox

Ambilight for Your Browser or: Monetizing an Add-on with Fat Plug

I’ve written a new Firefox extension; it’s called True Colors, and it bleeds the colors from the web page you’re viewing into the tab bar and status bar. Think of it as Ambilight for your browser.

The technical details behind the extension are interesting, but I won’t go into detail on that here, since Splashnology’s blog post describing how Ambilight for video works explains 99% of the technique.

There’s another important aspect to this extension. I’ve used it as a testbed for Fat Plug’s add-on monetization system. A Fat Plug-enabled extension will add/change ads on various websites, and, in turn, funnel a portion of the revenue from those ads to the extension developer.

There’s some controversy around this technique. Mozilla has opted to deny any Fat Plug extensions that are submitted to the Mozilla Add-ons Gallery. Website owners, I imagine, wouldn’t appreciate their ads being replaced with ads that don’t earn them any money. (Although it would harm them no more than ad-blocking extensions, which Mozilla does allow.)

However, to an add-on developer, the idea is intriguing: “What if I collected half of all the website ad revenue from all of the users that use my extensions?” A developer of a popular add-on could retire after a couple of years to the sands of Grand Cayman and spend his days writing free software that needs no monetization.

So True Colors is my testbed for Fat Plug’s technology. I won’t be uploading it to Mozilla Add-ons, and I won’t be publishing it anywhere that doesn’t make the Fat Plug integration obvious. I’m not looking to stealthily trick users into becoming my little monetization machines, which is why I purposefully wrote a simple extension that doesn’t add functionality to the browser as my first foray into Fat Plug.

If you’re interested in seeing how Fat Plug modifies ads on websites, you can install True Colors, agree to the license agreement, and then set the preferences extensions.fatplug.enableoutlinediv and extensions.fatplug.enableoutlinelink to true in about:config. Any ads that Fat Plug adds or modifies will be outlined in red for your convenience.

If you’re interested in the coloring functionality but are wary of the Fat Plug integration, you can install the extension and just not agree to the license agreement. That will keep the tab and status bar coloring functionality but disable Fat Plug’s code.

AutoAuth, Browser Add-ons, Mozilla, Mozilla Add-ons, Mozilla Fennec, Mozilla Firefox, Slashdotter, TwitterBar, YouTube Comment Snob

Four More Fennec Add-ons

Update: TwitterBar for Firefox was sold to HootSuite and renamed HootBar in March of 2011. TwitterBar for Chrome was discontinued in October of 2012.

Note: AutoAuth is now being developed by Steffan Schlein. If you would like to leave feedback, pleaseĀ create an issue on GitHub.

I got some great feedback after I updated URL Fixer to be compatible with Fennec, Mozilla’s mobile browser, and I’m happy to announce that I’ve been able to add Fennec compatibility to four more add-ons:

So far, I’ve found it pretty easy to port add-ons to Fennec, with the following caveats:

  • You can’t install add-ons in Fennec by opening them from your computer; I wrote a script to copy the add-on directly into the Fennec profile, much like an add-on IV drip – straight into the bloodstream!
  • There’s no easy access to the error console , but you can open it manually if you grab the address from Firefox.
  • No DOM Inspector. For now, just browse the source.

It seems that all of these issues could be solved with a “Fennec Add-on Development” extension; maybe that will be my next project, unless easier solutions already exist.

Feed Sidebar, Mozilla, Mozilla Add-ons, Mozilla Firefox

Feed Sidebar updated for Firefox 3

Firefox 3 introduced many new features for extension developers, and I decided to take advantage of some of them in order to update my Feed Sidebar extension. Version 3.0 of Feed Sidebar is now out, and these are the main features and changes I added:

  1. Look and feel: I updated all of the icons for the extension to blend in with Firefox 3’s new OS-specific look and feel. The sidebar’s toolbar uses the native theme icons, and the toolbar button is specifically designed to fit in on each of Mac OSX, Linux, and Windows. (The toolbar buttons for Windows, Mac, and Linux are shown respectively below.)

    Windows toolbar icon for Feed Sidebar Mac toolbar icon for Feed Sidebar Linux toolbar icon for Feed Sidebar

  2. Continuous updating: Feed Sidebar used to only check for feed updates when the sidebar was open; now it checks whether the sidebar is open or not (and notifies you when it finds updates). Big improvements in memory usage and performance were necessary to make this possible.
  3. Offline capabilities: the extension now caches all of your feeds, so if you go offline, you still have access to all of the data that was in the feeds, and you can read it while offline. When you go offline, Feed Sidebar goes into “Offline Mode”, and automatically opens the stored summary from the feed when you click on an item rather than trying to open the webpage the item references. This features makes use of the new online/offline events in Firefox 3.Here is a screenshot of what offline reading looks like:

  4. Places integration: when you add or delete a live bookmark in Firefox 3, Feed Sidebar will detect that via Firefox 3’s nsINavBookmarksService interface. When you add a new feed, it will instantly appear in the sidebar, and the reverse is true for deleting a feed.
  5. Caching: as soon as you start Firefox, Feed Sidebar will fill the sidebar with the feeds you were reading the last time Firefox shut down, even if you are now offline. This is made possible via the new JSON libraries that shipped with Firefox 3.

Feed Sidebar 3.0 is now available at Mozilla Add-ons.