Transferred size: 657KB. The contest task is almost completed, however audio files are not supported. Shared Media is empty for chats with one photo, the GIFs tab is also empty.

The overall speed is above average, however the app is not smooth during initial loading, when viewing chat history, viewing animated stickers, switching between chats and Shared Media tabs. Imperfections identified during Stage 1 have mostly been fixed, however it’s still not possible to log in with prefixes from certain countries. Chat history sometimes gets stuck on scrolling.

The design largely complies with provided mockups. The chat background blinks, the right sidebar with blurred previews is always opened after opening a chat. Media and stickers blink when sending, long captions break media bubbles. Message search should have been implemented in the right sidebar, search results are highlighted incorrectly.

Other imperfections identified during testing:
– macOS: reversed scroll breaks chats history, it gets duplicated when scrolling;
– GIFs are recognised as video files and not looped;
– Not possible to send a photo as a file.
– When sending media without a caption, the caption box is highlighted in red.

On the positive side, the context menu for messages has been implemented. Sadly, the ‘Forward’ button doesn’t work.

UPD

Sizes for all contestants were measured on one account. The general approach is:
1. Open the app in Incognito mode and check Transferred Size in Developer Tools > Network.
2. Reload the page, log in, Disable Cache in Developer Tools, clear Network tab, and check Transferred Size, taking into account service worker and its cache. That's the current transferred size.

UPD 2

Transferred size on startup: 424KB
Transferred size after logging in: 657KB

Private search must be on the right sidebar, not left.
you need chat virtualization too, so as not to create a load when the story is very large.
when you click on the message, you need to highlight the line.

+Chat popups.
+live editing/deleting messages, cool.
+media upload popups.
+clipboard media by ctrl+v .
+virtualization in sidebars, but no chat...
+layout is good, chats is beautiful, name/avatars colors correspond to the real .version.
+emojies, replies with stickers.
+caching.
+message send by enter, shift+enter new line.
+media players, selfie circle and default player, smooth progress bars, but no thumbnails photo (default player).
+text input before clicking on the field
+smooth media and video player animations.
+audio are working.
+download/upload files with loaders.
+follow by username from forwarded message.
+global, private search.

1. Shared media tab isn't working
2. Message search in the wrong place (needs to be in right sidebar)
3. Issue with scroll (video attached)