I believe my article on Hacks (<a href="https:&#x2F;&#x2F;hacks.mozilla.org&#x2F;2016&#x2F;01&#x2F;web-push-arrives-in-firefox-44&#x2F;" rel="nofollow">https:&#x2F;&#x2F;hacks.mozilla.org&#x2F;2016&#x2F;01&#x2F;web-push-arrives-in-firefo...</a>), linked from the marketing article, answers all of those questions at a high level and points to docs with more detail.<p>In short, there&#x27;s a single, persistent websocket connection between you and a broker service run by your browser vendor. Each subscription has a unique, anonymous URL on that service that gets provided to the website. To prevent abuse, there are throttles &#x2F; quotas &#x2F; limits imposed on push messages that do not show user-visible notifications.<p>The source to Mozilla&#x27;s broker, autopush, is at <a href="https:&#x2F;&#x2F;github.com&#x2F;mozilla-services&#x2F;autopush" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;mozilla-services&#x2F;autopush</a>. We recently rewrote it from Go into Python, which we now run with PyPy in production.