Working with responsive frameworks can make responsive web design cleaner and easier and considerably reduce development time.
The fact that responsive frameworks combine responsive and mobile-first web design, CSS pre-processing languages, and other cutting edge trends makes them one of my favorite topics to follow in web development.
The revolution in mobile technology has spurred some dramatic changes in web design and development. Because increasing numbers of people access the web via smartphones and tablets, a major part of a developer’s job is to ensure that sites are accessible and good-looking anytime, anywhere, and on any device. This has all happened so fast that there really hasn’t been much time to catch up; a range of ideas about a lot of new issues, like how to handle serving up images and how font sizes are determined on different devices, are still being discussed and seem to change daily.
One idea that has become accepted as a viable starting point for a long term solutions is ‘Responsive Web Design’. The term ‘Responsive Web Design’ was introduced in 2010 in a List Apart article by Ethan Marcotte who later authored a book by the same title. The ultimate concept behind responsive web design is to build sites that ‘respond’ fluidly and flexibly to different devices based on screen width. This approach allows a site to be designed in such a way that ensures it will look good on any device without a bunch of device specific media queries or a separate mobile version of the site. To get an idea of what this means, you can view this site in a desktop browser and watch how it ‘responds’ as you re-size the window.
To harness the power of responsive design, and implement some agreed upon best practices, a few responsive frameworks emerged, most notably Twitter Bootstrap and Zurb’s Foundation. These frameworks are essentially just templates consisting of HTML, CSS, and JavaScript files that can be used as a blank slate for development of responsive sites. They both include responsive grids, a core component of responsive design, and a number of other responsive components that can be tweaked and modified at will. Foundation and Bootstrap are currently developed as open source projects on github and currently represent two of the most popular Github repositories.

Luke Wroblewski extended the popular Responsive Web Design philosophy by formally introducing the concept of mobile-first web design. Although he used the term as early as 2009 it caught on when his book Mobile First was released in 2011. Wroblewski proposed that instead of designing sites for desktop screens that work on phones, sites should be designed for phones that work on desktops. Sounds odd but it makes sense: instead of simplifying the site and subtracting elements as screen sizes get smaller (Graceful Degradation), the site should become more robust and content should be added as screen sizes get larger (Progressive Enhancement). I just finished reading Mobile First and Responsive Web Design is at the top of my book list. You can get a deal if you buy them both together.
The web community has embraced the mobile-first idea as can clearly be seen by the decision by Bootstrap, Foundation, Google and WordPress to adopt a mobile-first design approach. Foundation has already completed the transition with the release of version 4 in January 2013 but The Bootstrap 3 release candidate is still in development with no official release date. Bootstrap 3 will not be backwards compatible with older versions so it seems somewhat impractical to start any new projects with it until the new version arrives. That being said, Bootstrap is the most popular of the two frameworks and, having used it, I can confirm that it was very pleasant to work with and ended up being a wonderful tool. I’m definitely excited for the release of version 3 and I’ll continue to consider it for future projects.

Sidenote for WordPress people (and others): The WordPress codex states that “The term ‘Theme Framework’ currently has two meanings 1. A “drop-in” code library that is used to facilitate development of a Theme, and 2. A stand-alone base/starter Theme that is intended either to be forked into another Theme, or else to be used as a Parent Theme template.” Personally, I think the use of the word by WordPress creates ambiguity and it annoys me that it encourages use of the term ‘frameworks’ as a fancy way to refer to what are essentially parent themes. For example, Genesis by Studiopress is heavily marketed as a framework when it is essentially a WordPress parent theme with some built in functionality. You have to pay for it and you are encouraged to buy their child themes but, in my experience with Genesis, it doesn’t really offer any exceptional features that aren’t already supported by the WordPress API or the numerous dedicated plugins that are available for free. I’m also a little annoyed by the misleading, out of context and possibly misquoted testimonial from WordPress founder, Matt Mullenweg, on the Genesis homepage but that’s another rant. In a separate funny example, one informative wpmu.org post lists Bones as one of “7 Free, Modern Starter Frameworks for WordPress Designers” while the Bones website prominently states that “Bones is not a Framework.” It’s actually a “per-project template” that might be worth checking out if you are considering developing a theme. The point I want to make here is to be aware that the term framework has different meanings in different contexts. I use framework to refer to a collection of core files for designing a website that can be used to build a site from scratch, used in php files-or in this case incorporated in to a WordPress theme (ie Bootstrap and Foundation).
Foundation and Bootstrap have both been integrated into a number of WordPress themes, many of which are also hosted as open source projects on Github. These themes, for the most part, are intended to be used as parent themes and simply pull in the frameworks’ core files with minimal modification. Several that I have used include wp-bootstrap and wp-foundation—both by 320press, Required+—built on Foundation 3 and Reverie—the only one of these currently built on foundation 4. I designed my site live in the browser using the core bootstrap files and later merged it into a Reverie child theme. I really like Reverie and I highly recommend it. I wasn’t too impressed with required+ but if I recall correctly it does have a cool off canvas layout template that may be useful to some people. Both of the 320press themes are nice and I used wp-foundation on the bootstrap project I mentioned previously. I’ll be watching all of them for updates. For more on using Foundation with WordPress, check out this article from WPMU.org
I expect Bootstrap, Foundation, and perhaps some other frameworks that haven’t hit the scene yet, to continue to gain popularity. I’ve spoken to several people involved in web development indirectly and directly who were entirely unfamiliar with either of them. While they are fairly new, they are some excellent tools and certainly something that should be have on on every web developer’s radar.