Aerogramme

Aerogramme is an open-source IMAP server targeted at distributed infrastructures and written in Rust. It is built on top of Garage, a (geographically) distributed object storage software. Aerogramme thus inherits Garage resiliency: its mailboxes are spread on multiple distant regions, regions can go offline while keeping mailboxes available, storage nodes can be added or removed on the fly, etc. Not only does it inherit its resiliency, but it also shares the burden of data management. Aerogramme can be seen as a proxy between the IMAP protocol and Garage protocols (S3 and K2V); it does not handle any data on its own and can be freely moved between machines. Multiple instances can also be run in parallel. As emails are very sensitive, Aerogramme encrypts users' mailboxes with their passwords. Data is decrypted in RAM upon user login: the Garage storage layer handles only encrypted blobs. Aerogramme is to our knowledge the first IMAP server to be designed from the ground up with object storage in mind. Thanks to this design, it is resilient and easy to scale.