EHR Integration Services for Health Apps: Patient-Facing and Provider-Facing

EHR integration is not one problem. It is two distinct problems that share some infrastructure but diverge significantly in authorization model, data flow, and compliance scope.

The first is patient-facing integration: the patient is the user of your application, and they authorize it to access their own health record. The second is provider-facing integration: the application exchanges clinical data with EHR workflows on behalf of clinicians, care teams, or the health system itself. Conflating these two at the architecture stage is one of the most common causes of EHR integration rewrites.

Momentum has built EHR integrations across more than 30 digital health projects covering both patterns. We work with any EHR system. The integration approach is determined by what the system exposes and what your application needs to do.

Patient-Facing EHR Integrations

Patient-facing integrations are used when your application serves patients directly: telehealth platforms, remote patient monitoring apps, patient engagement tools, chronic disease management applications, and consumer health apps that pull clinical context from a provider's EHR.

The authorization model is patient-context SMART on FHIR. The patient logs in, grants the application access to their record, and the application retrieves data through FHIR R4 resources: Patient, Observation, MedicationRequest, Condition, Appointment, CarePlan, and related resources depending on the clinical domain.

Key technical considerations:

• Token management per patient. Each patient's access is governed by their own OAuth token. At scale, this means managing token refresh across a large number of individual authorization grants, not a single system-level credential.
• Patient portal API surfaces. Epic's MyChart FHIR API and Cerner's patient-facing APIs have specific sandbox approval processes and profile extensions. AthenaHealth's patient-facing API moves faster through third-party approval. These differences affect timeline more than technical complexity.
• Scope negotiation. SMART on FHIR scopes determine which FHIR resource types the application can request. Getting scope configuration right in the initial approval submission avoids delays when you need access to additional resource types later.
• Data availability varies by instance. A health system running Epic may have specific FHIR profiles disabled or resource types unavailable on a given instance. We surface those gaps in discovery before they become scope changes mid-project.

Common patient-facing use cases:

Provider-Facing EHR Integrations

Provider-facing integrations are used when the application is part of a clinical workflow. The users are clinicians, care coordinators, administrators, or the EHR system itself. Authorization is system-to-system: a server credential or backend service, not a patient login.

Use cases include clinical decision support tools, care management platforms, referral management systems, EHR-to-EHR data exchange, population health platforms, prior authorization automation, and any application that needs to respond to clinical events such as admissions, discharges, or lab results rather than patient-initiated actions.

Key technical considerations:

• HL7 v2 is still dominant in many environments. NextGen, Altera, Veradigm, and a significant portion of community hospital deployments surface clinical events through HL7 v2 feeds, not FHIR APIs. ADT (admission, discharge, transfer), ORU (lab results), and SIU (scheduling) message types cover the majority of provider workflow integration use cases.
• Bulk FHIR for population-level access. When you need to pull cohort-level data, FHIR Bulk Data Access (Group/$export) is the right protocol. Not all EHRs support it equally. Epic and Cerner have solid Bulk FHIR implementations; smaller systems may require batch FHIR queries or HL7 v2 batch files instead.
• System-to-system authorization. Backend service apps use the SMART Backend Services authorization profile (client credentials flow with asymmetric key authentication). This is simpler than patient-context authorization in terms of token management but requires separate registration and approval with each EHR vendor.
• Webhook reliability. Event-driven integrations that subscribe to ADT notifications or FHIR Subscriptions need robust retry logic. EHR systems do not guarantee message delivery, and behavior around subscription management varies significantly between vendors.

Common provider-facing use cases:

Which EHR Systems We Work With

Momentum integrates with any EHR system. The six systems with the highest US market coverage are Epic, Cerner/Oracle Health, AthenaHealth, NextGen, Veradigm, and Altera Digital Health, but the list of systems we've worked with extends well beyond those. If your target health system or practice group runs an EHR, we can integrate with it.

The integration approach depends on what the system exposes:

Our unified data model abstracts this: your application layer sees a normalized structure regardless of what the underlying EHR exposes. Custom adapters per EHR handle field mapping, value set normalization, and protocol differences. Adding a new EHR system does not require changes to the core application.

For Caily, a caregiving platform, we integrated seven EHR systems simultaneously and shipped on schedule. For InnGen, a medical testing platform, EHR integration work contributed to a 30% reduction in admin overhead and a 20% increase in adoption.

Engagement Process

A typical EHR integration project runs 8 to 13 weeks from discovery to go-live.

Implementation time is driven by four variables: number of EHR systems, protocol mix (FHIR vs HL7 v2), integration pattern (patient-facing authorization is more complex than system-to-system), and data sync requirements (near-real-time vs scheduled batch).

Discovery is the phase that prevents the most timeline risk. "Supports FHIR" in vendor documentation does not guarantee that the specific resources and operations you need are available on a given customer's instance. We surface those gaps in week two, before they become scope changes in week six.

Momentum holds ISO 13485 certification. Compliance is scoped in discovery, not added at the end. Clients using our pre-built compliance modules have cut compliance-related development time by up to 60%.

Technical Scope

Authentication and authorization: SMART on FHIR patient-context authorization for patient-facing apps. SMART Backend Services (client credentials with asymmetric keys) for provider-facing system integrations. OAuth 2.0 with per-provider token refresh logic.

Protocol handling: FHIR R4 and STU3 resource operations. HL7 v2 message parsing for ADT, ORU, and SIU message types. CCDA/CCD clinical document processing. Bulk FHIR (Group/$export) for population-level data access.

Reliability: Per-provider rate limit handling. Webhook delivery and retry logic. Sync scheduling with backoff and error recovery.

Data layer: Unified data model with provider-specific adapters for field mapping and value set normalization across ICD-10, SNOMED CT, LOINC, and RxNorm where required.

Compliance: HIPAA audit logging at the integration layer covering read and write events. BAA verification per EHR vendor. Security controls reviewed against HIPAA technical safeguard requirements.

What You Receive at Project Close

Integration documentation. Architecture covering each EHR system, data flows, authentication mechanisms, and provider-specific configuration.

Test suite. Unit tests for transformation logic and adapter behavior. Integration tests against sandbox environments for each connected EHR.

Compliance report. Audit log configuration, BAA status per vendor, and security scan results for your compliance team.

90 days post-launch support. Covers production issues, provider API changes, and performance monitoring. EHR vendors update APIs on their own release cycles. We track changes during hypercare and flag anything that requires action.

For a broader look at EHR integration patterns and common failure points, see our EHR Integration Guide: Patterns, Pitfalls, and What Actually Works in 2026.