private letters, live preview

letters is a self-hosted web editor for writing letters in Typst. Pick a template, edit it beside a live PDF preview, then download the finished letter.

Drafts stay in the browser tab and disappear with it. The server compiles Typst in-process, never writes edited source to disk, and makes no external requests by default.

What it does

• Lists reusable personal and business letter templates.
• Recompiles after each pause and keeps the last good preview visible.
• Shows Typst diagnostics beside the source.
• Stores temporary edits in sessionStorage, not on the server.
• Ships as one Rust binary with a templates directory.
• Supports HTTP Basic authentication or deployment behind a private reverse proxy.

Install

Build and run it from source:

git clone https://github.com/atamanroman/typst-letter.git
cd typst-letter
just build
./target/release/typst-letter

The default configuration listens on 127.0.0.1:8080 and reads templates from ./templates. Put a TLS reverse proxy in front before exposing it beyond a trusted network.

NixOS

Add the flake and enable its module:

{
  inputs.typst-letter.url = "github:atamanroman/typst-letter";

  imports = [ inputs.typst-letter.nixosModules.default ];

  services.typst-letter = {
    enable = true;
    listen = "127.0.0.1:8080";
    templatesDir = "/var/lib/typst-letter/templates";
  };
}

The module runs the service as a dynamic unprivileged user with the templates directory mounted read-only and a hardened systemd unit.

Read the full documentation and source.