Hi-- I work at Nylas. Happy to jump in here :) The sync engine handles all the compatibility or dozens of IMAP and Exchange servers, and uses a variety of heur

Hi-- I work at Nylas. Happy to jump in here :) The sync engine handles all the compatibility or dozens of IMAP and Exchange servers, and uses a variety of heuristics for real-time notifications. It also does the heavy-lifting for the huge amount of data in most people's mailbox. The N1 app can cache your entire archive in about 10% of the disk space required if you also download all unprocessed headers+attachments. Right now our search implementation just sends a proxy request to the IMAP search, so you'll get the same performance as Gmail web, Mac Mail, etc. It's not ideal. We're working on our own faster search system, but it's tough to build a huge distributed search cluster that handles tens of terabytes. (And is growing quickly!) If anyone here wants to work on that, we're also hiring. ;) N1 is built on Electron, which under the hood is Chromium+NodeJS so that comes with a bit of weight. But the app itself is pretty manageable. You can check out the source here: https://github.com/nylas/n1 https://github.com/nylas/n1