Hypercubic Hopper Launches — 'Cursor for Mainframes' Brings Agentic AI to COBOL and z/OS (YC F25)

Hypercubic AI·medium signal

YC F25 startup Hypercubic launched Hopper, the first agentic development environment for mainframes. It provides a natural language interface to TN3270 terminals, enabling AI agents to navigate z/OS, inspect datasets, write JCL, debug jobs, and query VSAM from a modern IDE. The platform transforms opaque COBOL codebases into searchable documentation. 81 points on HN with significant enterprise developer interest, targeting the estimated 240B lines of COBOL still in production.