EHR Integration and Interoperability: A Complete Guide

EHR integration is how a health app, platform or AI tool exchanges data with the electronic health record: reading patient data, writing results back, launching inside the clinician's workflow and keeping records in sync. Interoperability is the wider goal of getting data to move safely between organizations and systems. This guide explains the main standards, the integration options for the largest EHR vendors, the rules that shape the work and which of our articles to read next.

Most US integration work now centers on HL7 FHIR APIs, with HL7 v2 messaging still carrying a large share of hospital traffic. Since January 1, 2026, the ONC certification program uses USCDI version 3 as its baseline data set, according to the HTI-1 final rule.

Start here

1. Healthcare Data Interoperability Playbook: the business case, architecture patterns and how to measure progress.
2. FHIR vs HL7: A HealthTech Engineering Comparison: when to use FHIR APIs, HL7 v2 messages or both.
3. EHR Integration API: A Practical Reference Guide: the API types, authorization and what to test.
4. SMART on FHIR: What It Is and How It Works: how apps launch inside the EHR and get authorized.

Find the right article for your goal

Standards: FHIR, HL7 v2 and SMART

FHIR exposes clinical data as resources, such as Patient, Observation and Encounter, through REST APIs. HL7 v2 sends event messages, such as admissions and lab results, usually through an interface engine. Most products need both: FHIR for app access and queries, and HL7 v2 for real-time hospital feeds that have not moved to FHIR. SMART on FHIR adds a standard way to launch an app from the EHR and authorize it with OAuth 2.0 scopes, so the app receives only the data it needs.

Working with EHR vendors

Each vendor has its own developer program, registration process and list of supported resources and operations. In practice, read access is widely available, write access is narrower, and each customer usually has to approve or activate an app before it runs in their environment. Vendor details also change: Oracle Health, for example, no longer supports its DSTU2 FHIR APIs and directs developers to R4, according to its Millennium Platform documentation. Confirm capabilities against the vendor's current documentation and the customer's configuration before committing to a launch date.

Rules that shape integration work

• Information blocking: certified health IT developers, health information exchanges and networks can face civil money penalties of up to $1 million per violation for information blocking, enforced from September 1, 2023, according to HHS-OIG.
• Prior authorization APIs: CMS-0057-F requires impacted payers to send prior authorization decisions within 72 hours for urgent requests and seven calendar days for standard requests, and to implement a Prior Authorization API beginning January 1, 2027, according to the CMS fact sheet.
• National exchange: TEFCA connects Qualified Health Information Networks (QHINs), including eHealth Exchange, Epic Nexus and the Oracle Health Information Network, as listed in ASTP/ONC's history of TEFCA.
• Privacy and security: integrations that handle protected health information fall under HIPAA, and vendors need a business associate agreement with each covered entity they serve.

Planning an integration project

Start with the workflow, not the protocol: write down what data the product needs, in which direction and how quickly. Map each need to a FHIR resource, an HL7 v2 message or a vendor API, and note who owns each decision: your team, the EHR vendor or the customer. Test identity matching, terminology mapping and error handling as carefully as connectivity, because a successful API call does not prove the data was interpreted correctly. Finally, plan for operations after go-live, including monitoring, version changes and who responds when an interface fails.

If you are building EHR integrations, see our healthcare engineering services.

Conclusion

EHR integration combines standards (FHIR, HL7 v2 and SMART), vendor programs and regulation. Start with the four core articles above, use the goal table to go deeper on Epic, Oracle Health, interface engines, migration or prior authorization, and plan for customer activation and ongoing operations from the start.

If you want help planning or building an EHR integration, book a consultation with Ekipa's HealthTech engineers.

Frequently asked questions

What is EHR integration?

Connecting an application to an electronic health record so it can read and write patient data, launch in the clinician's workflow and keep records in sync.

Should I use FHIR or HL7 v2?

Usually both. FHIR suits app access and queries, while HL7 v2 still carries many real-time hospital event feeds.

What is SMART on FHIR?

A standard for launching apps from the EHR and authorizing them with OAuth 2.0 scopes, so each app gets only the data it needs.

Do EHR customers need to approve an app?

In most cases, yes. Vendor registration is not enough; each customer typically activates the app and decides which users can access it.

Which regulations affect EHR integration?

The information blocking rules, ONC certification requirements such as USCDI, CMS-0057-F for payer APIs, TEFCA for national exchange and HIPAA for privacy and security.