Show HN: Agentic interface for mainframes and COBOL

The first agentic development environment for the mainframe.

Use AI agents to navigate TN3270, inspect datasets, write JCL, debug jobs, query VSAM, and operate inside z/OS from a modern development environment.

Download for Windows

Need access to a mainframe?

Fill out the form and we'll send you credentials to try Hopper on our mainframe for free.

Built by leading minds behind the world's most advanced AI and technology

Our team unites top researchers, engineers, and strategists from pioneering companies and institutions—all focused on building systems that deliver real impact.

An agent that understands z/OS

Drives ISPF by panel ID, writes column-strict JCL, decodes spool failures into structured diagnostics, and queries VSAM as SQL.

Compile, test, ship in one prompt

Drives the JCL, parses JES return codes, NEWCOPYs into CICS, and pauses for your approval before every change.

Debug failed jobs without hunting through SDSF

Hours of SDSF triage in one @-tag. The agent decodes JESMSGLG, JESYSMSG, and SYSUDUMP into the abend code, failing step, and source line.

A real TN3270 terminal, when you need it

Works exactly like the TN3270 you've used for years. Full PF, PA, and attention-key support.

Pricing

Hobby

Includes:

• No credit card required
• macOS, Windows, and Linux
• Connect to your own mainframe
• All core Hopper features

Enterprise

Everything in Hobby, plus:

• SAML SSO
• MCP Server Access
• Admin and Model Controls
• Org-wide Privacy Controls
• No Model Training
• Priority Support
• On-prem / VPC Deployment
• SOC 2 & Pen Test Reports

Join our community

Connect with builders using Hopper, follow product updates, and swap ideas with the Hypercubic team.

Download Hopper, connect to your LPAR, and start shipping

macOS

• Apple Silicon.dmg · arm64
• Intel.dmg · x64

Windows

• Installer.exe · x64

Linux

• .debDebian, Ubuntu · x64
• .AppImageAny distro · x64