Safe Rust
No buffer overflows, zero C dependencies, clean cargo audit.
hypermail-rs
A complete Rust rewrite of Hypermail — converts UNIX mbox files into cross-referenced, browsable HTML archives. Drop-in replacement for C hypermail 2.4.0.
About
hypermail-rs reads one or more UNIX mbox files (or stdin) and
produces a set of interlinked HTML pages: one page per email message, plus index
pages sorted by date, subject, author, and thread. It is a
C hypermail 2.4.0
drop-in replacement — same .hmrc config format, same CLI flags,
existing scripts work without modification.
Written in safe Rust with no C dependencies. New additions include multilingual support, extended MIME handling, dark/light mode on generated pages, and a full-text search index.
Based on the original Hypermail by Kevin Hughes (1994) and Kent Landfield (1997+). Rust rewrite and maintainer: Akis Karnouskos.
Installation
From source
git clone https://github.com/hypermail-rs/hypermail-rs.github.io.git
cd hypermail-rs.github.io
cargo build --release
# binary: target/release/hypermailRequires a recent stable Rust toolchain. No external C libraries. See build requirements.
Usage
Common commands
# Convert a mailbox to an HTML archive
hypermail -m mailbox.mbox -d output/ -l "My Archive"
# Use a config file
hypermail -c archive.hmrc
# Read from stdin (pipe from fetchmail, procmail, etc.)
cat mailbox.mbox | hypermail -i -d output/ -l "Archive"
# Incremental update — append new messages only
hypermail -u -m new.mbox -d output/
# Overwrite an existing archive completely
hypermail -x -m mailbox.mbox -d output/ -l "Fresh Archive"
# Print version / show all config values
hypermail -V
hypermail -v -c archive.hmrcCLI flags
All flags are compatible with the original C hypermail 2.4.0.
| Short | Long | Description |
|---|---|---|
| -a | --archives | URL for "Other mail archives" link |
| -A | --append | Append mbox output to a parallel mailbox file |
| -b | --about | URL for "About this archive" link |
| -c | --config | Configuration file (.hmrc) |
| -d | --dir | Output directory |
| -g | --gdbm | Enable .hm2index header cache |
| -i | --stdin | Read from standard input |
| -l | --label | Archive title |
| -L | --language | Language code, e.g. en, de, ja |
| -m | --mbox | Input mailbox file |
| -M | --metadata | Use metadata files for attachments |
| -n | --hmail | List submission address |
| -N | --nonsequential | Hash-based filenames |
| -o | --set | Set a config option, e.g. -o showhtml=2 |
| -p | --progress | Show animated progress bar |
| -s | --suffix | HTML file suffix (default: html) |
| -T | --indextables | Use tables for index pages |
| -u | --update | Incremental update |
| -v | --verbose | Print all config variable values and exit |
| -V | --version | Print version and exit |
| -x | --overwrite | Overwrite existing message files |
| -X | --xml | Write HAOF XML archive overview |
| -1 | --readone | Single message in input |
| --no-generator | Suppress "Generated by hypermail-rs" footer | |
| --warnings | Show configuration warnings |
Config file
hypermail-rs reads .hmrc files in the same format as the original
C hypermail. CLI -o key=value overrides file settings.
Example archive.hmrc
mbox = /var/mail/list.mbox
dir = /var/www/archive/
label = Development Mailing List
language = en
defaultindex = thread
overwrite = 1
spamprotect = 1
showhtml = 2
indextable = 1
folder_by_date = %Y-%m
monthly_index = 1Key options
| Option | Type | Description |
|---|---|---|
| mbox | string | Path to input mailbox |
| dir | string | Output directory |
| label | string | Archive title shown in pages |
| language | string | UI language code (189 supported) |
| defaultindex | string | date · subject · author · thread |
| overwrite | bool | Overwrite existing message files |
| spamprotect | bool | Obfuscate email addresses in output |
| showhtml | int | HTML parts: 0 = strip · 1 = proportional · 2 = full |
| folder_by_date | string | Date-based subfolders (strftime format) |
| msgsperfolder | int | Max messages per subdirectory |
| usegdbm | bool | Enable .hm2index header cache |
| monthly_index | bool | Per-month summary index pages |
| yearly_index | bool | Per-year summary index pages |
| linkquotes | bool | Link quoted text back to originals |
| nonsequential | bool | Hash-based filenames |
Features
189 languages
All ISO 639-1/2 codes plus IETF BCP 47 private-use subtags, compiled in at build time.
Full MIME
RFC 2047 headers, RFC 2231 filenames, RFC 3676 format=flowed, multipart.
Smart threading
Two-pass algorithm: header-based plus subject heuristics for maximum thread coverage.
Security
HTML escaping, CSP meta tags, MIME allowlist, path traversal protection.
Accessible output
Dark/light mode, ARIA landmarks, skip links, responsive layout on every archive page.
Fast incremental
.hm2index cache — append messages without rebuilding the full archive.
Thoroughly tested
Extensive test suite validated on large real-world mbox corpora. CI on Linux, macOS, Windows.
Download
Releases
Source archives and pre-built binaries (when available) are published on GitHub Releases.
View releases on GitHub ↗From source
Clone and build with cargo. Requires Rust 1.91+.
git clone https://github.com/hypermail-rs/hypermail-rs.github.io.git
cd hypermail-rs.github.io
cargo build --release