- A TN3270 terminal. A clickable, copy-pasteable rendering of the mainframe’s 24×80 green-screen interface.
- A datasets browser. Filter, click, and preview mainframe files inline without typing IDCAMS commands.
- A jobs browser. Watch JES queue entries change status in real time without opening SDSF.
- A chat agent. A panel that runs alongside the terminal. It reads source, submits jobs, decodes records, and writes changes under your supervision.
Start here
Quick start
Install, connect, add an API key, and run your first AI task.
How Hopper works
How the agent drives ISPF, JCL, and JES through one mainframe session.
What it’s for
Mainframes run core systems at most large banks, insurers, governments, and airlines. They use a 1970s block-mode terminal, JCL, and EBCDIC fixed-format files. Modern tooling expects HTTP, JSON, and UTF-8. Common mainframe requests and how Hopper handles them:| Request | Hopper’s actions |
|---|---|
| Read this dataset | FTP retrieve, EBCDIC-to-ASCII transcode, return UTF-8 text |
| Submit this job | Generate JCL, submit via JES, poll, fetch spool |
| Press PF3 | Send the TN3270 attention key, wait for host response |
| Decode this VSAM record | Parse the COBOL copybook, decode each field, return structured data |
| Run a SQL query over production data | Snapshot to a local file, query that |
What the chat agent does
You ask in plain English. The agent picks the right operations and runs them.- “Show me what
CBACT01Cdoes.” It reads the COBOL from the source PDS and walks you through it. - “This job failed last night — what happened?” It pulls the spool, classifies the abend, points at the offending step.
- “Add a check for negative balances to the validation paragraph.” It reads, edits, recompiles, reports back. You approve before any write.
- “How many accounts have a balance over $1M?” It snapshots the VSAM file, decodes via copybook, runs SQL.
Who uses it
- Mainframe developers who want a modern interface and an AI assistant that understands JCL, COBOL, and CICS.
- Engineers onboarding to a mainframe codebase, who need to read and reason about old code without years of context.
- Modernization teams encapsulating mainframe systems behind modern APIs.
Where it fits in modernization
Mainframe modernization usually means rehosting, rewriting, refactoring, or encapsulating. Hopper is for the encapsulating phase: read what’s running, understand the data, test interactions before you commit to a direction. It does not migrate, rewrite, or translate COBOL.What Hopper doesn’t do
- No mainframe-side install. The product runs on your laptop.
- No bulk data movement. Hopper reads and writes datasets; it doesn’t move data between systems.
- No production change management. The deploy feature targets dev and test environments.
Learn the basics
How Hopper works
How the four panels share one mainframe session.
The AI agent
Turns, tool calls, history, and approvals.
Tools
What the agent can do, and how Hopper keeps you in control.