Content is divided into episodes of 600 to 5,000 words, each of which can contain a title (shown at the beginning in large text) and an author note (shown at the end in italics.)
In terms of formatting, Amazon intentionally dumbed it down. Only text is allowed with no special characters such as emoji. The only formatting supported is bold, italic, and underline. Some common e-book formatting features not allowed are indented paragraphs, centering or right alignment, lists, tables, fonts, text sizing, hyperlinks, and images.
Currently Vella is only available via the web and the Kindle iOS app with support in the Kindle Android app to follow. No mention is made of making it available on e-ink Kindle devices or the PC/Mac apps. I have seen no indications that Vella will ever be coming those platforms.
I did some investigation to determine the format and technology behind this new reading experience. The website (
https://www.amazon.com/kindle-vella) and the iOS app are implemented very differently.
Vella on iOS
The Vella experience in the Kindle iOS app treats each episode much like a Kindle e-book. It allows customization in font, size, justification, and other characteristics. However episodes are always displayed in scrolling mode. Paged viewing is not supported.
Episodes are stored on the device and can be viewed offline. Standard book reading features, such as dictionary lookup and annotations, are available. Reading position, highlights, and annotations sync between devices.
Episodes download in Amazon's proprietary KFX format with strong DRM.
Vella in a web browser
The implementation of Vella on the web is quite different. The Vella reading experience in a browser is not customizable. Font, size, justification, and line spacing cannot be changed by the consumer. Annotations and highlights made using the iOS app do not appear. Offline viewing is not supported.
The website delivers each episode as HTML text with no encryption other than that provided by HTTPS. It is rendered in a way that disables the simple copying of text from the web browser, but there is no other DRM involved. It is fairly easy to copy episode content using the debugging features built into browsers, such as Inspect in Chrome.
Locked episodes are only partially downloaded so it is not possible to use the Inspect trick to obtain unpaid content. However once a paid episode is unlocked it's full content is downloaded and becomes potentially copyable.
I find the lack of customization, DRM, and other reading features to be surprising. Amazon has already implemented a more flexible reading experience and strong DRM in their
Kindle Cloud Reader. I suspect that the current web implementation of Vella was rushed and that a more full featured and locked down version will be coming eventually.