Named after the theoretical particle that moves faster than light.

Fast, secure, modern web-based email client.

A fork of SnappyMail, which itself forked RainLoop Webmail Community edition.

Existing SnappyMail installations can upgrade directly to Tachyon.

Requirements

• PHP 8.2+
• PHP mbstring extension
• OpenSSL or Sodium extension
• No database required

License

Tachyon is released under GNU AFFERO GENERAL PUBLIC LICENSE Version 3 (AGPL). http://www.gnu.org/licenses/agpl-3.0.html

Copyright (c) 2025 - present Tachyon Copyright (c) 2020 - 2024 SnappyMail Copyright (c) 2013 - 2022 RainLoop

What changed from SnappyMail

Compatibility

• Existing SnappyMail installations upgrade in-place — data directory and config are unchanged
• User-installed plugins using RainLoop\ or SnappyMail\ namespaces continue to work via compatibility shims

PHP

• PHP 8.2 minimum (dropped support for 7.4, 8.0, 8.1)
• Namespaces: RainLoop\ → Tachyon\, SnappyMail\ → Tachyon\Util\
• PHP 8.1 enums replacing abstract constants: ResponseType, StoreAction, MessagePriority, SignMeType, Layout, DkimStatus
• Dead code removed: register_globals ini_set, PHP 7.x compatibility shims

Security

• Content-Security-Policy: fixed report-to implementation with Reporting-Endpoints header; report-uri kept as fallback
• Permissions-Policy header added: denies camera, microphone, geolocation, payment, USB
• Subresource Integrity (SRI) hashes for all static JS and CSS assets

Features

• Undo send: configurable delay (Off / 5 / 10 / 20 / 30 seconds) before SMTP delivery; per-user preference
• Multi-account unread count badge on the account switcher button

Build and toolchain

• Rollup v4, ESLint v9 flat config
• GitHub Actions CI: PHP syntax check and JS/CSS lint on every push and pull request
• Release archives named tachyon-*.tar.gz
• OpenPGP.js updated to v5.11.3
• Removed unused marked.js vendor library

What SnappyMail changed from RainLoop

• Privacy/GDPR friendly (no: Social, Gravatar, Facebook, Google, Twitter, DropBox, X-Mailer)
• Admin uses password_hash/password_verify
• Auth failed attempts written to syslog
• Fail2ban support
• ES2020
• PHP mbstring extension required
• Replaced pclZip with PharData and ZipArchive
• Dark mode with option to strip background/font colors from messages
• Removed BackwardCapability (class \RainLoop\Account)
• Removed ChangePassword (re-implemented as plugin)
• Removed POP3 support
• Removed background video support
• Removed Sentry error tracking
• Removed Spyc yaml
• Removed OwnCloud bundling
• CRLF => LF line endings
• Embedded boot.js and boot.css into index.html
• Removal of legacy JavaScript (native APIs used throughout)
• Added modified Squire HTML editor replacing CKEditor
• Updated Sabre/VObject
• Split Admin / User / Sieve JavaScript bundles
• Better memory garbage collection
• Service worker for push notifications
• Advanced Sieve scripts editor
• Replaced webpack with rollup
• No user-agent detection (use device width)
• Plugin loading as .phar supported
• AddressBook contacts support MySQL/MariaDB utf8mb4
• Fetch Metadata Request Headers checks
• Reduced DOM size
• Kolab groupware support
• Extended IMAP RFC support (CONDSTORE, QRESYNC, METADATA, NOTIFY, and more)
• Sodium and OpenSSL encryption support
• PGP: OpenPGP.js v5, GnuPG, Mailvelope; ECDSA and EDDSA key support

Supported browsers

No Internet Explorer. No Edge Legacy.

• Chrome 90+
• Edge 90+
• Firefox 115+ (ESR)
• Opera 76+
• Safari 15.4+

JavaScript size comparison (RainLoop 1.17 vs SnappyMail vs Tachyon)

js/min/*	RainLoop	SnappyMail	Tachyon
admin.min.js	256,831	41,719	41,317
app.min.js	515,367	202,101	203,861
boot.min.js	84,659	2,231	2,273
libs.min.js	584,772	110,646	110,224
sieve.min.js	0	45,504	45,377
polyfills.min.js	32,837	0	0

For a user, the payload is around 66% smaller than traditional RainLoop.

PGP

RainLoop uses OpenPGP.js v2. Tachyon (via SnappyMail lineage) uses OpenPGP.js v5 with GnuPG and Mailvelope support. ECDSA and EdDSA key generation included.

HTML Editor

Squire is used in place of CKEditor.

	normal	min	gzip	min gzip
squire	122,321	41,906	31,867	14,330
ckeditor	?	520,035	?	155,916