Modernizing California’s healthcare enrollment platform for 17 million consumers

The California Healthcare Eligibility, Enrollment, and Retention System (CalHEERS) is accessible to 39 million California residents and helps with accessing, comparing, and selecting free or low-cost health insurance plans. Supported by system integrator Deloitte, it is a crucial resource for establishing access to quality healthcare for all, particularly those with lower incomes.

CalHEERS currently assists approximately 17 million Californians, with its usage spiking during enrollment season. At its peak, the system handles more than 6,000 unique visitors per hour, including agents, service center and county users, and consumers. It processes up to 91 million transactions daily during the 2025 enrollment year. Originally built on a legacy platform in 2012 in response to the Affordable Care Act, the system struggled to cope with the growing volume of traffic, which affected performance and the user experience. The CalHEERS team decided to re-architect the platform in the cloud, taking a microservices approach and embracing open source tools that provide flexibility to quickly adapt to healthcare, regulatory, and legislative changes, accelerating updates while reducing vendor lock-in.

The team’s main priority was migrating the platform from on premise infrastructure to the Amazon Web Services (AWS) cloud. The second phase of the refresh program focused on modernizing the platform using microservices with Red Hat OpenShift. Many team members were already familiar with Red Hat solutions and a strong partnership existed between Deloitte and Red Hat, therefore, adopting a trusted hybrid cloud foundation for building and scaling containerized applications in Red Hat OpenShift seemed the natural choice. 

The migration process involved the transfer of 72 interfaces to a containerized environment within 7 weeks. The system currently supports 11 million user accounts and nearly 18 million individuals (including 15 million for Medi-Cal and 1.97 million through Covered California). During peak system usage, the CalHEERS team runs up to 5,000 containers across production and non-production environments. 

5 ways IT teams benefit from Red Hat OpenShift

Combining DevOps methodologies with their application of Red Hat OpenShift, the CalHEERS team has the flexibility to quickly implement updates while ensuring 24/7 system availability for Californian consumers. CalHEERS gained two key advantages: faster performance with 10% quicker response times, and cost-effective scalability— teams can spin up a new instance in just 15 seconds compared to 15 minutes previously. During the 2025 enrollment year, a record-high 1.97 million consumers enrolled in health plans and processed 170 million transactions. Red Hat OpenShift helped the CalHEERS team remain responsive to regulatory changes and shifting user needs. 

Updates to CalHEERS are now much faster, ensuring the best possible user experience without any delays. One such update included accelerating the time commitment to acknowledge and verify documents from days to seconds. With tens of thousands of documents uploaded weekly—many of which are vital for proving eligibility—this improvement means users no longer face obstacles that could impact their access to healthcare. 

Looking ahead, the team plans to introduce both artificial intelligence (AI) and human-based assistance to fully streamline the user journey, empowering consumers with quicker, more accessible support in selecting the right healthcare plan.

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