The Bootstrap Blog

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Bootstrap 4 Alpha 3

Alpha 3 has landed! We have an overhauled grid, updated form controls, a new font stack, tons of bug fixes, and more. It’s been several months since our last update, but the size of this update should help get us back on track.

Work on Alpha 3 started rather broadly, addressing bug fixes and docs updates of all shapes and sizes, but finished with a narrow focus on our form controls and grid system. If you’ve followed the development in our v4-dev branch, you might already be familiar with some of these bigger changes.

Skip to the updated alpha docs site, or keep reading for the highlights.

Grid system

The grid system was overhauled with three major pull requests—#19099, #20349, and #20361. Those PRs largely focused on the following changes:

These changes are available in our standard grid, as well as our flexbox grid. More on that below.


Flexbox auto-layout

Flexbox mode has been updated across the board in Alpha 3, starting from the grid system (it uses the same variable and the updated Sass mixins) and moving through our utilities and components.


Form validation states

Forms saw a ton of activity early on in Alpha 3’s development. Documentation, class names, layout options, and validation styles have all been drastically improved.

<div class="form-group has-success">
  <label class="col-form-label" for="inputSuccess1">
    Input with success
  <input type="text" class="form-control form-control-success" id="inputSuccess1">
  <div class="form-control-feedback">
    Success! You've done it.
  <small class="form-text text-muted">
    Example help text that remains unchanged.

System fonts

We’ve replaced the decades old Helvetica/Arial font stack with a system font stack, utilizing newer, more readable, and more powerful fonts that companies like Apple, Google, and Microsoft have specifically designed for today’s devices.

Originally this was planned to affect Linux users, but font usage and support is rather inconsistent across distros and user preferences. For that reason, there’s no intended font change for folks on Linux.

And so much more…

There were nearly 1,200 commits to Alpha 3 and this post barely scratches the surface. We’ve fixed dozens of other bugs and worked hard to improve our documentation across the board.

For more details on this release’s changes, take a look at the Alpha 3 ship list issue, as well as the closed Alpha 3 milestone.

Anxious to jump in? Then head to the v4 alpha docs!

Be sure to join our official Slack room! and dive into our issue tracker with bug reports, questions, and general feedback whenever possible.

What’s next?

More exploration, more bugfixes, more docs updates, and, best of all, more alphas. The daily grind keeps us super busy these days, but we’ll do our best to keep the momentum going. Stay tuned!

@mdo & team