IBM Compiler and Library for Rexx on IBM Z

Name: IBM Compiler and Library for Rexx on IBM Z
Brand: IBM

IBM Compiler and Library for REXX on IBM Z is a licensed IBM Z software product that compiles REXX source into a compiled form, provides a runtime library for executing compiled REXX programs, and supports execution primarily on z/OS (TSO/E) and z/VM (CMS).

Est 1911|Valuation $213.9B|Raised $85.3B

LinkedIn 19.8M|Website|Web traffic 18.9M|FTEs 287,000|HQ Armonk, NY

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IBM Compiler and Library for Rexx on IBM Z screenshot

01Competitive Landscape

Narrative analysis

Where the compiler/library is likely to be selected:
- When a significant REXX automation estate must remain on-platform and there is a need for control over packaging and runtime behavior.
- When distributing compiled REXX programs to other LPARs or customers is required (Alternate Library distribution).
Where alternatives may be preferred:
- Interpreted REXX: operational simplicity and ubiquity for ops scripts and quick tooling.
- Python/ZOAU: suitability for integration with modern CI/CD, REST APIs, and a larger talent pool.
Market trend context:
- IBM’s broader messaging has emphasized AI acceleration and modernization for IBM Z. Budget and strategic attention in some organizations may prioritize modernization workstreams; however, existing REXX estates remain operationally important in many enterprises.

- Where the compiler/library is likely to be selected: - When a significant REXX automation estate must remain on-platform and there is a need for control over packaging and runtime behavior. - When distributing compiled REXX programs to other LPARs or customers is required (Alternate Library distribution). - Where alternatives may be preferred: - Interpreted REXX: operational simplicity and ubiquity for ops scripts and quick tooling. - Python/ZOAU: suitability for integration with modern CI/CD, REST APIs, and a larger talent pool. - Market trend context: - IBM’s broader messaging has emphasized AI acceleration and modernization for IBM Z. Budget and strategic attention in some organizations may prioritize modernization workstreams; however, existing REXX estates remain operationally important in many enterprises.

	IBM Compiler and Library for REXX on IBM Z	Interpreted REXX (z/OS / z/VM base)	Python + ZOAU on z/OS (automation approach)
Starting Price	Quote-based / IBM licensing (not public)	Included with platform (varies by OS terms)	Python may be available on z/OS; ZOAU is an IBM-delivered toolset (pricing varies)
Most appropriate for	Enterprises with extensive REXX estates and organizations that need packaged/distributed REXX tooling	Teams needing quick, low-overhead automation	Teams modernizing automation and integrating with CI/CD and broader ecosystems
Key Strength	Compiled distribution model and runtime library integration; integration with classic Z tooling	Lowest friction and widespread availability on Z platforms	Modern libraries and ecosystem; larger hiring pool; easier integration with web services
Key Weakness	Cost and complexity; limited public ROI evidence; specialized expertise required	Performance trade-offs and source distribution/IP concerns	Requires modernization effort and different runtime/security patterns