They&#x27;ve had an HTML &#x2F; JS Add-in model for a few years now: <a href="http:&#x2F;&#x2F;dev.office.com&#x2F;getting-started&#x2F;addins?product=excel" rel="nofollow">http:&#x2F;&#x2F;dev.office.com&#x2F;getting-started&#x2F;addins?product=excel</a><p>It&#x27;s not the exact same as VBA macro extensibility, but you can do some pretty interesting stuff with it - build task panes, build embedded charts that leverage web content, etc.