I'm the sole developer of TabMail. I wanted my email client to have AI features, and ended up making a Thunderbird add-on and an iPhone app. I've now open-sourced both under MPL 2.0, and I wanted to share them here to get some community feedback, if possible.
I made a short video of both, since it's easier to show what they do than explain everything in a post. Hopefully you like it: https://tabmail.ai/demos/tabmail-promo.mp4
You can review a prepared reply, tell it what to change, or ask questions about your inbox and calendar. On TB, I wanted to do most of this with the keyboard. On the phone, I wanted to just talk to it :)
Code: Thunderbird: https://github.com/TabMail/tabmail-thunderbird iOS: https://github.com/TabMail/tabmail-ios
Note: I have the AI backend closed for now, since it does need me to fish compute from LLM providers, etc. Still, I made the email/calendar processing ZDR (zero data retention) since, as a solo dev, I didn't want to go through the headache of storing anyone's email or calendar data. The content can be sent for AI processing, but isn't kept on TabMail's servers. Search stays on-device.
Anyhow, please try it out! Just trying to share how I wanted email to be with AI features :) Happy to answer questions.
Downloads: https://tabmail.ai
PS. The Thunderbird add-on uses the Experiments API for things that aren't supported in MV3, so I'm hosting it on my website for now.