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  • 1.  Is Python now the main language to use on the Mainframe?

    Posted 01/06/26 06:11 AM

    I am just opening this question as I have been asked, should Python be the primary programming language to use today as it does have a lot of versatility over some of the more traditional ones?

    Yes, I know it is going to depend on what you are doing but for example would you put Python before REXX as they can both do what you require.



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    Steve Spence
    Expert Systems Engineer, Applications
    Ensono Ltd
    London
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  • 2.  RE: Is Python now the main language to use on the Mainframe?

    Posted 01/06/26 06:40 AM

    When Python can invoke ISPF dialogs like Rexx can, I'll think about it.

     

    Regards,

    Marcus Davage CEng CITP MBCS

    Lead Product Developer
    Intelligent Z Optimization and Transformation
    BMC Software Ltd
    Email marcus_davage@bmc.com

    MarcusDavage@bmcsoftware.onmicrosoft.com/bookings/">Book time to meet with me

    My Digital Pin IBM Champion 2025 badge image. Experience. Advanced level. Issued by IBM

     






  • 3.  RE: Is Python now the main language to use on the Mainframe?

    Posted 01/19/26 10:57 AM
    Edited by Don Leahy 01/19/26 11:00 AM

    Yes!  People in my shop regard me as a Rexx expert, but if you look at my code you will see that the Rexx language elements I use are very simple, my code consists primarily of function calls to ISPF, DB2, SDSF, IMS or other environments.  That, in my opinion, is the real value that Rexx brings.  I really don't care how easy or hard it is to code a linked list or binary tree in Rexx; I have never had the need to do that.    

    To be fair, my opinion is influenced by the fact that I have little need to invoke Unix commands or services.  (Though I do like BPXWDDN as an alternative to TSO's ALLOC).  



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    Don Leahy
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    Original Message


  • 4.  RE: Is Python now the main language to use on the Mainframe?

    Posted 01/08/26 02:58 PM
    REXX and Python can, in many scenarios, solve similar problems, they belong to different worlds within z/OS and serve distinct needs.
     
    REXX is a mainframe-native language, deeply integrated into z/OS. It fits naturally into the TSO/E and ISPF universe, allowing for the execution of system commands, automation of ISPF dashboards, direct manipulation of datasets, and generation or submission of JCLs with extreme simplicity. Being part of the traditional ecosystem, REXX is usually available in virtually any z/OS environment, without the need to install additional runtimes or external libraries. This characteristic makes it a safe and stable choice for operational automations and day-to-day administrative tasks.
     
    Python, on the other hand, is not native to z/OS, but today it is well established in the environment through Unix System Services (USS) and initiatives such as z/OS Open Tools and IBM SDKs. Its main strength lies in its vast ecosystem of libraries and the ease of working with modern integrations. Tasks such as consuming REST APIs, parsing JSON, automating pipelines, analyzing logs, and integrating with external tools are much more natural in Python than in REXX.
     
    In short: it depends on the goal.


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    Matheus Porsch
    Systems Administration - Kyndryl
    Brazil
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  • 5.  RE: Is Python now the main language to use on the Mainframe?

    Posted 06/01/26 08:38 AM

    Personally, if I were starting something new today, I'd lean towards Python over REXX in most cases.

    That's not because REXX is a bad language. In fact, REXX has served the mainframe world extremely well for decades and is still very effective for many z/OS scripting and automation tasks.

    The advantage Python brings is the broader ecosystem around it. You get access to a huge developer community, countless libraries, API integration, automation frameworks, data analytics, and increasingly AI-related capabilities. It's also a skill that transfers across platforms, whether you're working on IBM Z, Linux, cloud, or distributed environments.

    That said, I wouldn't advocate replacing working REXX code just for the sake of modernization. If an existing REXX solution is stable, maintainable, and doing the job, there's often little business value in rewriting it.

    My view is simple: keep REXX where it makes sense, but for new development and automation projects, Python would generally be my first choice because it gives you more flexibility and future-proofs your investment in skills and tooling.

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    Abhishek Anand

    IBM Z & LinuxONE Brand Leader,

    SBM, Riyadh, 

    Saudi Arabia

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    Abhishek Anand
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