KiTTY is a feature-rich fork of PuTTY, the free Windows SSH/Telnet client. This branch is a forward-port of the entire KiTTY feature set onto current PuTTY 0.84 — so you get KiTTY's extras on top of a modern, security-patched PuTTY core (≈1,200 upstream commits newer than KiTTY's original 0.76b base).
⚠️ Beta release (0.84.1.61-beta). The full KiTTY feature set on a modern, security-patched PuTTY 0.84 core — including a post-quantum key-exchange warning and a console CLI key generator (kittygen-cli.exe). Please still read the known issues below.
(click an image to enlarge)
The configuration dialog (start KiTTY with no session):
A terminal session with a clickable, underlined hyperlink:
Grab the latest build from the Releases page →.
Current release — KiTTY 0.84.1.61-beta:
| Download | Use it when |
|---|---|
| Installer — per-user (no admin) | Recommended. Installs for your user only, no UAC prompt (%LOCALAPPDATA%\Programs\KiTTY). |
| Installer — system-wide | All users, into Program Files (requires admin). |
| Portable ZIP | No install — run from a folder or USB stick. Includes kitty_portable.exe and all command-line tools. Executables are not UPX-packed (antivirus-friendly). |
| Portable ZIP (UPX) | Same contents with kitty.exe/kitty_portable.exe UPX-packed for the smallest download. Some antivirus engines dislike UPX — if in doubt, take the standard ZIP. |
Both installers add Start-Menu + Desktop shortcuts and an Add/Remove-Programs entry, and uninstall
cleanly. Every download is checksummed (SHA256SUMS in the ZIP), and all executables are
Authenticode-signed.
~46 KiTTY features are ported and verified, including:
- Window: transparency, maximize / fullscreen / saved position on start, always-on-top, roll-up, send-to-tray (auto + on-minimize), per-session icons, background image.
- Hyperlinks: clickable URLs in the terminal (Ctrl+click configurable) with underlining.
- Sessions & automation: auto-command after login, auto-password, anti-idle keepalive,
port-knocking, duplicate-session, immediate-quit, session export/import, scripting (rutty),
and an in-terminal command console (Ctrl+F8, type
/help; seedocs/COMMANDS.md). - Proxies & jump hosts: reusable named proxy definitions (including SSH jump hosts), selectable per session.
- Security: saved passwords encrypted at rest — Windows DPAPI in registry mode, an opt-in master password for the portable store (travels between machines); a post-quantum key-exchange warning; a built-in update checker that verifies the download's Authenticode signature chain.
- SSH agent (kageant): per-key or global use-confirmation, key-use notifications, a
remembered startup-key list, a Windows-OpenSSH-agent bridge,
kitty.iniconfiguration and registry-free autostart for portable installs. - Transfers / backends: ZModem send/receive, WinSCP & kscp file transfer with directory-aware uploads (OSC 7 — see the callout below), adb (Android) backend.
- Terminal: font resize, protect, print, negative/B&W colours, clear/restart log, far2l extensions.
- Storage: registry or portable file/dir storage (
kitty_portable.exe),kitty.iniconfiguration. - Plus the standard PuTTY tools, renamed KiTTY-style:
klink,kscp,ksftp,kageant,kittygen. kittygen-cli.exe— a console-mode CLI key generator (generate, convert, fingerprint) for use in scripts and pipelines. Runkittygen-cli --helpfor options.
📂 Put your files where your
cwdis. Turn on OSC 7 directory tracking and drag-and-drop uploads — and Start WinSCP — land in your shell's current remote directory instead of always dropping into$HOME. It's the safe, data-only rework of KiTTY's old "send file to the current directory" trick, which was retired after that mechanism turned out to be a remote-code-execution hole (CVE-2024-23749): the new one only ever reads a strictly-validated path and never runs anything the remote sends. Two lines in your shell startup do it — OSC 7 how-to →.
Most KiTTY extras read from a kitty.ini ([KiTTY] section). The release includes an inert kitty.ini.example with every supported key commented out; copy/rename it to kitty.ini only when you want an active config file. For example, URL hyperlinks are enabled with:
[KiTTY]
hyperlink=yesdocs/KITTY-INI.md explains the settings file — how KiTTY finds it, the savemode/portable rules, and all its sections — and links the fully annotated kitty.ini.example. See FEATURES.md for the full feature reference, including how to enable each one, and CHANGELOG.md for what changed in each release.
This is a beta: most KiTTY features are restored and verified, but a few have limitations
or still want real-world testing. The full, per-release list is in
KNOWN-ISSUES.md — current highlights:
- Antivirus / SmartScreen & UPX — the standard ZIP ships only plain, uncompressed signed
executables. The
-upx.zipflavour and the installers carry UPX-packedkitty.exe/kitty_portable.exe(smallest download), which can trip heuristic AV — if flagged, use the standard ZIP. - far2l shared clipboard (GET) — remote→clipboard (SET) is verified end-to-end; the GET direction (remote reads your clipboard) transmits over SSH only, not raw (a pre-existing PuTTY behaviour).
- far2l clipboard "Ask" mode (Window → Selection) — answering OK grants the remote clipboard access for the rest of the session (no per-request reprompt). Set it to Disabled to deny.
- adb backend & rutty scripting — verified against test fixtures, not yet against a real Android device / live remote shell.
- Stored passwords — saving passwords is optional; saved ones are encrypted at rest: Windows DPAPI in registry mode (bound to your account/machine), an opt-in master password in portable mode (travels between machines; it is never stored — if you forget it, the passwords it protected are unrecoverable). Neither defends against malware already running as your user; for the strongest security prefer SSH keys (kageant).
- Command-line tools use the registry session store —
klink/kscp/ksftpdo not read a portable (savemode=dir) store, so portable sessions and their master-password-protected passwords are usable from the GUI only. - Diagnostic dumps —
/savedumpredacts the known high-risk secret fields (passwords, passphrases, key files, clipboard, login-automation strings and inline script content — including inside the bundledcurrent.ktx). - Background image — the thin margin outside the terminal cell grid is still solid-filled (cosmetic).
Found something else? Please open an issue.
Cross-compiled to Win64 with MinGW + CMake (Ninja) under WSL/Linux:
cmake -B build-mingw -G Ninja -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain-mingw.cmake
cmake --build build-mingw # whole tree
cmake --build build-mingw --target kitty # just kitty.exeThe MSI installers are built from windows/installer/ with WiX v5.
For an orientation on how this fork is structured and ported — architecture, the MOD_* /
parallel-target approach, and the constraints to know before editing shared files — see
PORTING.md.
- PuTTY © Simon Tatham and the PuTTY team — the upstream this is built on (putty homepage).
- KiTTY © Cyril Dupont (9bis) — the feature fork this port carries forward (https://www.9bis.net/kitty/).
- far2l terminal extensions (the far2l shared clipboard) — derived from the putty4far2l project: far2l's PuTTY extensions originally by Ivan Sorokin, putty4far2l by unxed, the 0.78.5 port by Ivan Shatsky; the far2l file manager by elfmz and contributors.
- This 0.84 port keeps PuTTY's MIT licence — see
LICENCE.
The original PuTTY source README is preserved as README.