Understanding the Payer-to-Payer API: Requirements, deadlines, benefits and trends

Updated February 10, 2026

When patients in the U.S. switch health plans, they often face disruptions in care due to incomplete or inaccessible health records. For payers, these gaps in data exchange lead to inefficiencies and frustrated members experiencing interrupted care.

Enter the Payer-to-Payer API, a key component of the U.S. Centers for Medicare & Medicaid Services (CMS)’s push for interoperability. This API aims to ensure that essential patient data flows smoothly between payers, reducing administrative burdens and supporting better care continuity for members.

Let’s dive into what this API entails, exploring its requirements, benefits, and emerging trends in the industry.

What is the Payer-to-Payer API?

The Payer-to-Payer API, part of the CMS Interoperability and Prior Authorization Final Rule, is a FHIR-based interface that facilitates the transfer of patient data between payers when individuals move between health plans or have concurrent coverage in the United States. It allows payers to exchange claims, encounters, prior authorizations, and other critical health data securely and efficiently. 

Who does this impact?

The Payer-to-Payer API is a requirement for “impacted players” (CMS-regulated payers), which includes:

• Medicare Advantage (MA) organizations
• Medicaid managed care plans
• State Medicaid and CHIP Fee-for-Service (FFS) programs
• Children’s Health Insurance Program (CHIP) state agencies and managed care entities
• Qualified Health Plan (QHP) issuers on Federally-Facilitated Exchanges (FFE)

What types of data are required?

The API mandates the exchange of: 

• Claims and encounter data (excluding provider remittances and enrollee cost-sharing information) 

• Prior authorization information: Details about existing or past prior authorizations (excluding those for drugsand those that were denied) 

• USCDI data classes and elements: Includes standardized clinical and non-clinical health data. 

Impacted payers are only required to share patient data with a date of service within five years of the request for data. For patients with concurrent coverage, payers must exchange data quarterly to maintain up-to-date records. 

Payers must also provide plain-language educational resources to patients that explain the benefits of the API. It’s important to note that members must explicitly opt in for their data to be shared through the Payer-to-Payer API to ensure compliance with privacy laws.

When does this come into effect? 

Impacted payers must comply with the Payer-to-Payer API requirements by January 1, 2027. Dates vary by program type—for some impacted payers the requirement aligns to a rating period or plan year beginning on or after January 1, 2027

4 key benefits of the Payer-to-Payer API

1. Enhanced member satisfaction: Transitions between health plans are often a source of frustration for members due to delays in transferring their health data. The Payer-to-Payer API ensures that critical patient information is seamlessly transferred, empowering members with continuity of care, and avoiding duplication of tests and treatments. This not only strengthens member trust but also reduces complaints and churn rates. 
2. Reduced admin burden: Manual processes are resource-intensive and can lead to errors. By automating data exchange, the API alleviates administrative workloads. Payers save time and reduce costs associated with faxing, phone calls, and manual data entry while improving accuracy and operational efficiency. 
3. Support for value-based care models: Value-based care requires comprehensive data to measure outcomes, track performance, and manage costs. The API ensures that new payers have access to the patient’s recent history, enabling effective management of chronic conditions, care planning, and coordination. This alignment supports value-based reimbursement models, ultimately benefiting both payers and patients. 
4. Compliance with CMS Standards: Adhering to CMS requirements ensures payers avoid penalties and positions them as leaders in the healthcare ecosystem, fostering trust among regulators, providers, and members.

3 industry trends for payers in 2026

With the introduction of the Payer-to-Payer API, there are some key trends emerging: 

1. Transition to FHIR: FHIR is rapidly becoming the universal language for healthcare data exchange. The Payer-to-Payer API reinforces the trend of adopting FHIR-based standards, ensuring seamless interoperability across systems. This trend is driving payers to modernize their IT infrastructures to remain competitive and compliant. 
2. Support for concurrent coverage data exchange: The requirement to exchange data quarterly for patients with concurrent coverage highlights the growing demand for real-time, ongoing data updates. This pushes payers toward adopting systems capable of handling continuous data integration and sharing. 
3. Expansion of voluntary data sharing: While the API is mandatory for specific scenarios, some payers are recognizing the value of broader data sharing. Voluntarily expanding the API’s use to include fraud prevention, program integrity, or other purposes is emerging as a strategic opportunity for forward-thinking payers. 

Take the next step

The Payer-to-Payer API represents a significant step forward in enabling seamless data exchange to support continuity of care. For payers, it’s an opportunity to improve member satisfaction, streamline operations, and enhance care delivery while aligning with CMS standards. 

At Firely, we specialize in helping payers implement FHIR-based APIs. As the deadline for implementing the Payer-to-Payer API approaches, let’s work together to turn compliance into a strategic advantage. Take the next step with Firely Server, which offers all the tools and support you need to get started. 

For more detailed instructions, visit our CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F) documentation, or reach out to our team to explore how Firely can support your journey to interoperability.