Pepsi Manual

Pepsi is a mail transfer agent and crypto gateway written in Rust. It receives mail over SMTP, authenticates it at the boundary, and then advances each message through a configurable chain of small stage programs — ARC sealing, SRS envelope rewriting, end-to-end encryption and decryption, DKIM signing, bounce generation, mailing-list processing and delivery (direct-to-MX, via a smarthost, or locally) — preserving the authentication verdicts the final receiver needs.

Those programs are chained over a single shared database table. Each processing step is its own program, so the pipeline can be reordered, individual steps replaced, and new behaviour added by dropping in another program — without touching the rest of the system.

Start with Introduction, which says what Pepsi is, lists its features, compares it with the established MTAs and explains how the rest of this manual is organised. Getting started on a cheap VPS is the walkthrough from DNS to a first received e-mail, and The Wizard shows the pipelines pepsi-setup --wizard builds and what each of its questions decides.

Contents

Indices