The toast component is like an alert box that is only shown for a couple of seconds when something happens (i.e. when the user clicks on a button, submits a form, etc.).

Default markup

<div class="toast show" role="alert" aria-live="assertive" aria-atomic="true" data-autohide="false" data-toggle="toast">
  <div class="toast-header">
    <span class="avatar avatar-sm mr-2" style="background-image: url(...)"></span>
    <strong class="mr-auto">Mallory Hulme</strong>
    <small>11 mins ago</small>
    <button type="button" class="ml-2 close" data-dismiss="toast" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="toast-body">
    Hello, world! This is a toast message.
  </div>
</div>

Translucent

Toasts are slightly translucent, too, so they blend over whatever they might appear over. For browsers that support the backdrop-filter CSS property, we’ll also attempt to blur the elements under a toast.

<div class="toast show" role="alert" aria-live="assertive" aria-atomic="true" data-autohide="false" data-toggle="toast">
  <div class="toast-header">
    <span class="avatar avatar-sm mr-2" style="background-image: url(...)"></span>
    <strong class="mr-auto">Mallory Hulme</strong>
    <small>11 mins ago</small>
    <button type="button" class="ml-2 close" data-dismiss="toast" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="toast-body">
    Hello, world! This is a toast message.
  </div>
</div>

Stacking toasts

If you want to stack toasts just put them in the same container.

<div class="toast show" role="alert" aria-live="assertive" aria-atomic="true" data-autohide="false" data-toggle="toast">
  <div class="toast-header">
    <span class="avatar avatar-sm mr-2" style="background-image: url(...)"></span>
    <strong class="mr-auto">Dunn Slane</strong>
    <small>11 mins ago</small>
    <button type="button" class="ml-2 close" data-dismiss="toast" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="toast-body">
    Hello, world! This is a toast message.
  </div>
</div>
<div class="toast show" role="alert" aria-live="assertive" aria-atomic="true" data-autohide="false" data-toggle="toast">
  <div class="toast-header">
    <span class="avatar avatar-sm mr-2" style="background-image: url(...)"></span>
    <strong class="mr-auto">Mallory Hulme</strong>
    <small>7 mins ago</small>
    <button type="button" class="ml-2 close" data-dismiss="toast" aria-label="Close">
      <span aria-hidden="true">&times;</span>
    </button>
  </div>
  <div class="toast-body">
    This is another toast message.
  </div>
</div>