One of the nice things about the way we do things with RunKit embeds (https://runkit.com/docs/embed) is that the code lives in your site, not on ours. The API generates the embed the same way something like highlight.js generates syntax-colored code on your site. That means if we're ever down, your site gracefully degrades to a not-runnable snippet, as opposed to merely disappearing like this seems to or with embedded gists.