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About Hopper
What is Hopper?
A desktop app that puts a TN3270 terminal, dataset/job browsers, and an AI agent in one window, so you can work with z/OS mainframes from a modern interface. See What is Hopper? for the full picture.Who makes it?
Hypercubic. We build modern tooling and AI for z/OS mainframes.Does it run on Windows / Linux / macOS?
Yes! Go to the download page to get the latest build for your platform.Do I need a mainframe to use Hopper?
Yes. Hopper requires a successful connection to a z/OS system to enter the main UI. Without a reachable mainframe, you can’t get past the connection modal. If you don’t have one, email us for credentials to test Hopper against our mainframe environment. Or run your own — the AWS CardDemo is a public sample environment that works well with Hopper.Will it install anything on my mainframe?
No. Hopper sits entirely on your laptop and uses standard FTP + TN3270. Your sysprog doesn’t need to deploy anything.Cost
Is Hopper free?
Hopper is free to download and use. You’ll need an Anthropic API key for the AI agent, which Anthropic charges for per-token.Will there be a paid version?
We may introduce paid tiers in the future. Today, Hopper is free.Setup and connection
What do I need to start?
- A z/OS mainframe with TN3270 reachable from your laptop. FTP is optional but recommended — it powers the datasets browser, jobs browser, builds, and most agent tools.
- A TSO user ID and password for FTP, if you’re using it. You can also add this later from Settings → FTP.
- An Anthropic API key (for the AI agent)
Does it work over a VPN?
Yes. As long as your laptop can reach the mainframe’s TN3270 port (and FTP port if you’re using FTP-backed features), Hopper works the same way.Does it support TLS?
Not yet. Hopper currently connects to plain TN3270 and FTP. TLS support (FTPS, TN3270 over TLS) is on the roadmap.Can I connect to multiple mainframes?
One at a time today. Use Edit Connection in the terminal panel header to switch the active host. Saved profiles for multiple mainframes are on the roadmap.Security and data
Where does my data live?
- Credentials: encrypted secure store on your laptop, with the encryption key managed by your OS keychain
- Taps and logs: your laptop’s user data folder
- Mainframe data: on the mainframe, except for what you explicitly snapshot or read
What does Hopper send to Anthropic?
When you use the agent, your prompt and recent chat context (with hidden field content redacted) go to Anthropic’s API. The agent’s responses come back. We don’t send:- Mainframe credentials
- Hidden field content
- Files outside the active conversation
- Any data from other apps
Does Anthropic train on my prompts?
By default, no. Anthropic’s standard policy doesn’t train on API customer data. Always check their current policy at anthropic.com/legal/privacy.Does Hypercubic see my data?
No. Hopper is a desktop app and doesn’t talk to our servers during normal operation, other than to check for updates.Are credentials sent to the AI?
No. The agent never sees raw credentials. When it invokes a tool that needs credentials (likecics_signon), the tool call carries no credentials. Hopper’s sidecar process loads them from the secure store and applies them when the tool runs.
What happens to passwords I type into the terminal?
Hidden fields (including password fields) are masked before they cross any boundary. The agent and logs see bullets (•), one per typed character, instead of the actual content.