Email has been with us for decades. The basic format works almost everywhere, but that compatibility also means it has evolved slowly.
Foxy Mail is a native macOS mail client that adds two independent capabilities to ordinary IMAP email: message compression and accessible content encryption.
They solve entirely different problems.
Email compression is long overdue
Compression is standard almost everywhere else.
Websites compress HTML before transmitting it. Backups are compressed before storage. Photos, videos, applications, and documents all use formats designed to reduce their size.
Email bodies, however, are generally stored and transmitted without modern compression. Long HTML messages, signatures, formatting, and repeatedly quoted conversations accumulate in every participating mailbox.
Compression without ZIP attachments
Foxy Mail can compress the message body with ZSTD before sending it.
The app handles the entire process automatically. There is no archive to create, no ZIP attachment to open, and no additional action for the recipient.
The message is composed and read like any other email.
Compression means:
- Less data is transferred
- Messages occupy less mailbox space
- Long conversations create less unnecessary bulk
If a recipient does not support Foxy Compress, the email is sent normally.
Email encryption has a different history
Protecting email content is not a new idea.
PGP dates back to the early 1990s, while S/MIME has also been available for decades. Both can provide strong protection, but neither became part of everyday email for most people.
The problem was rarely the underlying encryption. It was everything surrounding it: generating keys, exchanging them, importing certificates, understanding trust, and ensuring that every recipient was correctly configured.
As a result, most people rely only on transport encryption.
TLS protects the connection while a message travels between a device and a mail server. It does not necessarily protect the stored message from whoever controls or gains access to that mailbox.
Content encryption inside Foxy Mail
Foxy Mail can encrypt the message body with AES-256 when the necessary recipient keys are known.
The encryption happens before the message leaves the Mac.
Foxy Mail learns supported capabilities and public keys from messages exchanged between its users. Once the recipients are known, encryption can become part of the normal sending process instead of a separate technical exercise.
A display name proves very little
Foxy Mail also examines incoming messages.
An email may display the name of a bank, delivery company, or colleague. That visible name can be chosen freely and is not proof of who sent the message.
The Identity Inspector reveals the details behind it:
- Actual From address and domain
- Reply-To address
- Return-Path
- SPF, DKIM, and DMARC results
A message claiming to come from one company but directing replies to an unrelated domain becomes much easier to recognize.
See where links really lead
Visible link text does not have to match the real destination. Messages can also contain tracking hosts, deceptive domains, hidden redirects, and QR codes with unexpected payloads.
Foxy Mail extracts this information and shows it in the Trust Inspector.
Sender and link domains are checked against HaGeZi protection lists. The findings contribute to a visible message grade:
Clear · Review · Risky · Danger
Instead of presenting only an unexplained spam label, Foxy Mail shows the reasons for the grade.
Local attachment scanning
Downloaded attachments are checked on the Mac using YARA rules, EICAR signatures, and additional heuristics. ZIP archives are unpacked so that their contents can also be inspected.
When the scanner detects a suspicious pattern, the message grade escalates and the reason appears in the Inspector.
Messages and attachments are not uploaded to an external scanning service.
Still a normal IMAP mail client
Foxy Mail works with existing IMAP and SMTP accounts. There is no need to change your email address or move to a new provider.
It supports multiple accounts, standard mailboxes, drafts, replies, forwarding, searchable local mail, Apple Mail–compatible color flags, duplicate detection, and an offline, compressed .eml store.
Passwords remain in the macOS Keychain.
There is no Foxy Mail account, no telemetry, and no subscription service between the app and your existing mailbox.
Email does not have to stand still
Compression can make email more efficient without changing how people write or read messages.
Encryption can protect the content beyond its journey to the mail server — without forcing ordinary users to become certificate administrators.
These are separate improvements with separate purposes. Foxy Mail brings both into a native macOS client while keeping regular IMAP email at its core.
Available for macOS 14 Sonoma or later on Apple Silicon and Intel Macs.
