What's Wrong with Heritage Pega UI Frameworks?

Heritage Pega UI frameworks like UI-Kit and Theme Cosmos rely on server-rendered pages in which each click or interaction triggers a full rebuild of the screen on the back end.

The reason for this design is that, when the systems were first released, the digital landscape looked a lot different. Browsers were much less capable and varied widely in their abilities, so server-side rendering provided better performance and security. Furthermore, keeping all rendering logic on the server gave IT departments tighter control and, in turn, ensured greater consistency.

However, today’s heavier workloads and higher user expectations mean that, while this legacy design worked in the past, in modern times it creates bottlenecks, namely:

• Each request increases CPU and memory usage on the server
• Higher traffic increases the risk of slowdowns, especially at peak times
• Scaling often requires more infrastructure, which drives up cloud spend

While this might seem like minor friction in day-to-day use, it can snowball into higher costs and lower productivity as workloads grow.

The bottom line is that heritage Pega UI frameworks still function, but they are not designed for modern expectations of speed and scalability. Over time, your business could feel the impact.

How Constellation Improves Performance

Constellation takes a different approach. Instead of relying on the server to rebuild entire screens, it uses a client-side engine that renders most of the interface in the user’s browser. This shift reduces pressure on the server and speeds up responses.

Key improvements include:

• Fewer server calls – The second-generation DX API v2 is leaner than its predecessor, delivering only what’s needed
• Lighter payloads – Data transfers are smaller, so pages load faster
• Consistent performance at scale – More users can be handled without additional infrastructure.

This architectural change ensures performance gains scale with your business as it grows. By moving the heavy lifting off the server and onto the browser, Constellation provides a platform that feels faster, costs less to run, and adapts as demand increases.

Watch this video for a deep dive into the features of Constellation. 

Scalability Without the Overheads

Growing case volumes and user numbers often force IT teams to add infrastructure. But simply scaling hardware is a costly and reactive approach.

For example, annual global data creation continues to grow fast, with research forecasting it to increase from 149 zettabytes in 2024 to 394 zettabytes by 2028. While this data is not all relevant to your Pega platform, it gives some insight into future growth rates.

Constellation makes growth more efficient by minimizing server strain at its core. Using the same infrastructure, it can support more users and more cases without constant upgrades. That means:

• Lower hosting bills by reducing cloud resource use
• Predictable performance even during peaks
• The ability to grow capacity strategically, not reactively

Instead of paying to scale inefficient applications, Constellation allows you to scale smarter, extending the life of existing infrastructure and delivering better ROI.

The Business Impact of a Pega Upgrade

Performance and scalability may sound technical, but the business effects are far-reaching. Faster applications mean:

• Streamlined workflows – Teams can handle more cases each day
• Improved customer journeys – Customers see quicker responses and smoother processes
• Reduced downtime risk – Lower server strain decreases the chance of slowdowns or outages

These improvements can have a significant effect on your bottom line. They reduce cost per transaction, strengthen customer loyalty, and give your organization the agility to compete in fast-moving markets.

Ultimately, Constellation brings performance upgrades that go beyond technical efficiency to deliver measurable operational gains.

Pega Modernization on Your Terms

Every organization has a different appetite for change. Many start small, piloting Constellation for a single high-impact case type or phasing migration across departments. Others choose a greenfield approach, upgrading in one hit, building fresh without carrying forward technical debt.

At first, it can seem daunting, but a partner like Labb can help make it more manageable. We can assess your current environment, model the ROI of different approaches, and design a tailored roadmap that balances business goals with practical risk management.

With the right plan and proper risk management, modernization becomes a much smoother process.