A Mainframe RPA Manifesto
Mainframe RPA| by Jerry Rackley

If you’ve been following HostBridge over the past year, you cannot miss the focus we have on mainframe Robotic Process Automation (RPA). Our emphasis on mainframe RPA came from a customer who was experiencing the consequences of high volume screen scraping being done by RPA bots. Our investigation of RPA activity within this enterprise was revealing:

  1. Screen scraping is the default method for RPA bots to integrate with screen-based mainframe applications.
  2. RPA bots are capable of generating high transaction volumes on the mainframe. The RPA developers are often oblivious to the impact of their automations on the host. The IT group, on the other hand, found this activity alarming.
  3. All the RPA vendors seem able to easily invoke RESTful services as a better alternative to screen scraping.

Since these mainframe RPA findings have come to light, the HostBridge team is actively evangelizing the RESTful services method for creating automations that reach the mainframe. We now offer a series of free “how-to” guides and other resources for using RESTful services with RPA.

RPA Adoption Surges

recent Blue Prism survey shows that enterprises are embracing RPA and the benefits it provides. According to the survey report, 92% of decision makers feel RPA is a key means of driving digital transformation, while 79% see RPA as a solution to global productivity problems. At HostBridge, we’re advocates of RPA and the benefits it can provide. We know that within an enterprise, automations will often include mainframe applications. Our message is simple: when automations do reach the mainframe, use RESTful services to accomplish integration. Don’t pay the screen scraping tax!

Many enterprises are, however, paying the screen scraping tax on their mainframe automations. Most don’t know it – yet. It happens when RPA developers, unaware of the consequences of screen scraping, develop and deploy such automations. The built-in, default mainframe integration methods in solutions from the major RPA vendors rely on screen scraping. When RPA bot activity scales up, screen scraping on a massive scale uses a disproportionate amount of mainframe resources. This makes the IT caretakers of the mainframe nervous, as they have responsibility for managing mainframe resources and paying for them.

A Mainframe RPA Manifesto

Implementing RPA in an enterprise doesn’t have to be a zero sum game: RPA developers win; mainframe loses. When screen scraping prevails as the method of integrating bots to the mainframe, RPA is a zero sum game. However, creating RESTful services for mainframe integration lets every stakeholder win:

  • Automations are more reliable, impervious to screen geometry changes that cause screen scraping integrations to fail.
  • Performance is much better, from 10X to 60X improvement in HostBridge benchmarks.
  • Mainframe cycle consumption is kept to a minimum.

The disadvantages of RPA bots that scrape screens spawned one HostBridge customer to develop a mainframe RPA manifesto of sorts, which we summarize and endorse here:


  1. Avoid vendor lock-in that results from screen-based automations.
  2. Agree that RESTful services are the preferred interface and architectural standard for mainframe integration, rather than screen scraping.
  3. Avoid promoting the development of RPA that relies on screen scraping.

This short manifesto makes great sense for any enterprise using RPA with the mainframe. Why? Because enterprises deploying mainframe automations at scale that screen scrape will consume more mainframe resources than necessary. They will also experience slower performance, and if mainframe applications change any, automation failures. It’s very easy to avoid these potential problems by using RESTful services instead.

Prototype RESTful Services

The HostBridge team offers the HostBridge JavaScript Engine (HB.js), a lightweight, federated RPA platform that runs within CICS on the mainframe. HB.js automation scripts are easily invoked by Automation Anywhere, Blue Prism, UiPath, and other RPA automations. Enterprises that wish to prototype RESTful services with their mainframe RPA can get free trial HB.js software and support to prototype this approach. Just reach out to us using the contact information at the bottom of this page to get started.

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