● Free · 100% browser-based · No sign-up

Understand your mainframe.
In minutes, not months.

Reforge analyzes your JCL and COBOL files, rebuilds the map of your z/OS system, and helps you plan modernization — before you touch a single line of code.

Launch the analyzer ⚡ Try with a sample system

Your files never leave your browser. No upload, no account, no server.

reforge — system map
PAYRUN0JCL JOB CBPAY100COBOL CBPAY200COBOL · SQL PAYREC.CPY PAYROLL.MASTERDATASET · OUTPUT BANK.CUST.MSTRDATASET · INPUT

Three questions, answered

Every legacy modernization project starts with the same unknowns. Reforge answers them from the code itself.

🗺

What does this system do?

An interactive system map rebuilt from your JCL and COBOL: jobs, programs, datasets, and how they connect — even if the last person who knew has retired.

💥

What breaks if I change it?

Impact analysis and data lineage across jobs, steps and programs. Change a copybook, see exactly what to recompile and re-run — before you find out in production.

⚡

How do I modernize it?

AI-assisted COBOL → Python translation and plain-English system explanations, to accelerate understanding — not to blind-rewrite production code.

Everything, out of the box

Built for real mainframe estates, not textbook examples.

📂
Mixed formats, auto-detectedJCL, COBOL, copybooks, EBCDIC — drop them together, language is detected per file.
🔀
Job & program flowsSteps, PERFORM / CALL / GOTO paragraphs — visualized, not guessed.
🗄
DB2 / SQL awareEmbedded SQL, cursors and table usage detected and traced.
📋
Copybook resolutionRecord layouts resolved across programs, with recompile impact.
🔎
Data lineageFollow any dataset from input to output across the whole system.
🔒
Zero data exposureEverything runs client-side. Your code never leaves your browser.

From mystery to map in three steps

No project setup, no repository connection, no mainframe access needed.

Drop your files

Export or copy any set of JCL, COBOL and copybook files. Reforge detects each language automatically.

Explore the map

Browse the system map, flows, datasets and lineage. Assess the impact of any change in one click.

Plan modernization

Use AI explanations and COBOL → Python drafts to build a migration plan your team can actually defend.

Built for teams facing legacy

Modernization leads scoping a migration Architects assessing impact & risk New maintainers inheriting undocumented code Consultants auditing a client's estate
🔒

Your mainframe code is the crown jewels

That's why Reforge runs entirely in your browser. Files are parsed locally, nothing is uploaded, nothing is stored. The AI features use your own API key, stored on your machine only.

Stop guessing. Start mapping.

Free, instant, and nothing leaves your browser.

Launch the analyzer →