Transit vs PuTTY
Both terminals are free. The difference is what happens when something breaks — and what's standing between a junior tech and a production router while it does.
The short version
- Choose Transit when
- you work on network gear and want real session management plus an AI that can investigate a live device — proposing read-only, vendor-gated diagnostics you approve click by click — with the terminal costing exactly what PuTTY costs: nothing.
- Choose PuTTY when
- you want the smallest possible single-purpose tool — a tiny, portable, open-source binary that has been the trusted default for decades, with a full companion suite (pscp, psftp, plink, pageant) and, by explicit design, no AI at all.
What is PuTTY?
PuTTY is the free, open-source SSH and Telnet client that has been the default answer on Windows for nearly three decades. Written and maintained primarily by Simon Tatham and released under the MIT licence, it's small enough to run from a USB stick, ships a complete companion suite (pscp, psftp, plink, pageant, puttygen), and speaks to almost anything — SSH, serial, Telnet, Rlogin, even SUPDUP.
The project is deliberately conservative and says exactly what it is: release 0.83 added post-quantum key exchange, and the FAQ states plainly that PuTTY uses no AI or LLM in its operation. It does one job, has done it reliably since 1997, and asks nothing of you.
What is Transit?
Transit is an investigation-only network AI assistant built into a professional SSH and serial terminal. You connect to your switches, routers, and firewalls the way you always have — the AI investigates alongside you. It reads the same scrollback you see, proposes read-only diagnostic commands, and explains what it finds. It can investigate your network; it can't change your gear.
Investigation-only is architecture, not a promise. The AI has exactly four abilities — list open sessions, read redacted scrollback, propose a command, ask you a question — and every command it proposes must pass a per-vendor permit list and your explicit click before it runs. Always both, never either. Device output is redacted before any model sees it, and the AI has no code path to your credentials. Transit AI Software Inc. completed a SOC 2 Type I examination in July 2026, and the safety architecture is patent pending.
The terminal itself is a free download — multi-session tabs, serial console support, syntax highlighting, quick copy/paste, session export, and one-click import of your existing SecureCRT, MTPuTTY, MobaXterm, ssh_config, or CSV inventory — no account required. The AI is the subscription, when you want it.
Transit vs PuTTY at a glance
| Capability | PuTTY | Transit |
|---|---|---|
| Price & license of the terminal | Free, open source (MIT) — commercial use welcome [1] | Free download, no account required; closed-source commercial software |
| Platforms | Windows binaries (x86/Arm, installer, portable, Microsoft Store); Unix via source build [2] | macOS (Apple Silicon), Windows, Linux (.deb — Ubuntu 24.04+/Debian 13+) |
| Tabs & session management | Partialsaved sessions (stored in the Windows Registry); a tabbed multi-session UI is not advertised — one window per session [3] | Yesmulti-session tabs, groups, split panes; scrollback survives tab switches |
| Serial / console access | Yesserial sessions, plus Telnet, Rlogin, and SUPDUP [3] | YesUSB-to-serial console sessions alongside SSH |
| Bulk session import | Not offeredno session export/import documented; sessions live in the Registry [3] | Yesimports SecureCRT, MTPuTTY, MobaXterm, OpenSSH ssh_config, and CSV — PuTTY setups come across via ssh_config or CSV |
| AI in the terminal | Not offered“PuTTY does not use any AI or LLM during its operation” — the project's own FAQ, by design [3] | Yesan investigation-only network AI assistant that works your live sessions |
| Human approval on every AI command | n/a — no AI [3] | Yeseach proposed command passes a per-vendor permit list AND your explicit click — always both |
| Network-vendor awareness | Not offeredgeneral-purpose terminal [4] | Yesdefault-deny permit lists for Junos, Cisco IOS/IOS-XE/NX-OS/IOS-XR, Arista EOS, PAN-OS — plus bring-your-own-policy for anything else |
| Where AI data goes | n/a — no AI; everything stays on your machine [3] | device output is redacted before any model sees it; credentials stay in your OS keychain; no training on your data |
✓ offered · ◐ partial · — not offered / not what the tool is for. Bracketed numbers link to the PuTTY page each claim was checked against; the full source list with dates is at the bottom of this page.
Where PuTTY wins
- Tiny and portable: standalone single-file binaries, an MSI, and a Microsoft Store listing — it runs from a USB stick. ↗
- Genuinely open source under the MIT licence, free for any use including commercial. ↗
- A complete companion suite — pscp, psftp, plink, pageant, puttygen — that decades of scripts and runbooks already depend on. ↗
- Protocol breadth on legacy gear (serial, Telnet, Rlogin, SUPDUP) and a conservative, security-first release culture — post-quantum key exchange (ML-KEM) landed in 0.83. ↗
- If your policy requires zero AI in tooling, PuTTY states its position in writing: no AI or LLM, period. ↗
Where Transit wins
- Session management that matches how network engineers actually work: tabs, groups, split panes, bulk import, broadcast input.
- The investigation itself: an AI that reads the same scrollback you see, proposes read-only diagnostics, and explains what the output means — instead of you copy-pasting into a chat window.
- Structural safety on production gear: every AI-proposed command needs the per-vendor permit list AND your click; config and write verbs are blocked outright.
- Redaction before the model: PEM blocks, password hashes, keys, and tokens are stripped from scrollback before any AI sees it.
- Investigations end in a written summary you can paste into the ticket or the escalation.
Migrating from PuTTY — and what to keep it for
There's no one-click PuTTY import, because PuTTY has no documented session export —
saved sessions live in the Windows Registry. The practical route into Transit is an
OpenSSH ssh_config or a CSV of your inventory (only host is required), or MTPuTTY's exported server
list if you run PuTTY under MTPuTTY. Folder structure and key-file paths come across;
credentials never do — you enroll secrets once, straight into your OS keychain, and
Transit never reads a stored password from any imported file.
And keep a copy of PuTTY. It's the right tool on a locked-down jump box you can't install software on, on ancient gear that only speaks Rlogin, and in any environment whose policy says no AI in tooling — a position PuTTY's own FAQ states in writing. A free terminal isn't a reason to switch; what happens after the terminal opens is.
Frequently asked questions
Is Transit free like PuTTY is free?
The terminal is — free download, no account, no trial clock, full SSH and serial client. The difference in kind: PuTTY is open-source software under the MIT licence, while Transit is closed-source commercial software whose terminal tier is free. Transit's investigation-only AI is the paid subscription, with a 14-day trial.
Can Transit import my PuTTY sessions?
Not directly — PuTTY stores saved sessions in the Windows Registry and doesn't document an export format. Most engineers migrate by pointing Transit's importer at an OpenSSH ssh_config or a CSV of their inventory; if you use MTPuTTY on top of PuTTY, Transit reads MTPuTTY's exported server list. Credentials are never imported from any source — you enroll them once into your OS keychain.
Can Transit's AI change my devices?
No. The AI has exactly four abilities — list open sessions, read redacted scrollback, propose a command, ask a question — and every proposed command must pass a default-deny per-vendor permit list AND your explicit click. Config and write verbs are blocked. It investigates; it can't change your gear.
Why not just use PuTTY plus ChatGPT?
Because then the technician is copy-pasting production device output into a chat window and typing back whatever comes out. Transit redacts device output before any model sees it, refuses config verbs at a per-vendor permit list, and turns every proposed command into a button a human clicks. Safety isn't a prompt — it's the architecture, and that architecture is patent pending.
Try it yourself
The terminal is free. Really.
Download Transit and use it as your everyday SSH and serial client at no cost — no account, no trial clock. Add the investigation-only AI when you want it.
Free download · macOS · Windows · Linux · No account required
PuTTY is copyright 1997–2026 Simon Tatham and contributors, and is free software released under the MIT licence. Transit AI Software Inc. is not affiliated with, sponsored by, or endorsed by the PuTTY project or its maintainers; the PuTTY name is used only to identify the software being compared.
Comparison last verified July 20, 2026. Product capabilities, packaging, and pricing change — every PuTTY claim on this page was checked against PuTTY's own public pages on the dates below:
- PuTTY — official project page — checked July 20, 2026
- PuTTY FAQ (platforms A.3, storage A.5.2, serial A.1.1, AI A.10.2) — checked July 20, 2026
- PuTTY licence (MIT) — checked July 20, 2026
- PuTTY download page (0.84 binaries + companion tools) — checked July 20, 2026
Spotted something out of date or plain wrong? Report an inaccuracy and we'll fix it fast. Transit™ is a product of Transit AI Software Inc.