That is absolutely a good point. I should have shown my working a bit more. static is boring, because every email can still have a custom endpoint. proxyable

That is absolutely a good point. I should have shown my working a bit more. static is boring, because every email can still have a custom endpoint. proxyable is more interesting. You say "cacheable" - I don't see that in the AMP project notes: https://github.com/ampproject/amphtml/issues/13457 https://github.com/ampproject/amphtml/issues/13457 @ras9929 yes amp-list allows you to generate dynamic content populated from a json endpoint. The demo shown today did exactly what you are suggesting. See https://www.youtube.com/watch?v=p8Eo4gAoDBA&feature=youtu.be https://www.youtube.com/watch?v=p8Eo4gAoDBA&feature=youtu.be The only reason to host images remotely rather than including them as cid: links inside a multipart/related is size and encoding overhead. Likewise, a new dynamic multimedia format could be entirely self-contained within the email if you wanted to design it that way. Instead what we have is something which is very tightly coupled to short-lived online services. It's a really poor archival format, but it has just enough sweet bits that people will want to use it for things that it shouldn't be used for. It's really short-term design.