HTI-4 and Health IT Vendors: Why Interoperability Is Now a Product Requirement

• January 27, 2026

The ONC’s HTI-4 Final Rule marks a decisive shift for health IT vendors. Interoperability is no longer an implementation detail or downstream integration concern it is now a core product and certification requirement.

For EHR vendors, ePrescribing platforms, and healthcare technology companies, HTI-4 raises expectations around RTPB, ePA, updated SCRIPT standards, and certified FHIR APIs. These capabilities must now operate reliably at scale, not just exist on paper, to maintain ONC certification and meet provider expectations.

As the industry moves through transition periods ahead of the 2028 deadlines, vendors face a clear choice: treat HTI-4 as a compliance exercise or use it to modernize interoperability as a durable product capability.

Why HTI-4 Impacts Health IT Vendors First

Unlike providers or payers, health IT vendors sit at the center of HTI-4 compliance. The ONC Health IT Certification Program directly ties certification to demonstrable support for:

1. Real-Time Prescription Benefit (RTPB)
2. Electronic Prior Authorization (ePA)
3. Certified FHIR APIs
4. Updated ePrescribing standards (NCPDP SCRIPT)

If these capabilities are not built into the product, scalable by design, and standards-aligned, certification and therefore market eligibility is at risk.

The urgency is driven by real operational pain. Physicians complete an average of 39 prior authorizations per week, spending nearly 13 hours weekly on PA-related tasks. HTI-4’s automation mandates are designed to reduce this burden, but providers depend on vendors to absorb interoperability complexity rather than push it downstream.

Interoperability Is No Longer "Integration Work"

Historically, many vendors treated interoperability as:

1. Customer-specific interfaces
2. One-off payer connections
3. Post-go-live integration projects

HTI-4 removes that flexibility.

Under the new rule, interoperability must be:

1. Productized, not customized
2. Standards-first, not proprietary
3. Repeatable and auditable, not fragile

As a result, interoperability decisions now belong in product strategy and platform architecture, not just implementation or delivery teams. Vendors that continue to treat interoperability as “integration work” will struggle to scale under HTI-4 expectations.

What HTI-4 Requires Beyond FHIR and APIs

HTI-4 exposes a gap many platforms face: the difference between implementing standards and operating interoperability.

To meet HTI-4 certification and real-world performance expectations, vendors must operate interoperability across three interconnected layers:

1. Interface Performance

   FHIR, NCPDP SCRIPT, Da Vinci Implementation Guides, national vocabularies

2. Interface Workflows

   Transaction orchestration, routing, retries, error handling, payer variability

3. Data Workflows

   Validation, normalization, deduplication, reconciliation, and auditability

Most vendors focus heavily on the first layer. HTI-4 success depends on operating all three layers together, consistently and observably, in production environments.

Key HTI-4 Areas That Reshape Vendor Architecture

1. Updated ePrescribing: SCRIPT v2023011 as a Foundation

   HTI-4 modernizes ePrescribing by mandating alignment with newer NCPDP SCRIPT standards.

   For vendors, this requires:

   1. Dual support for SCRIPT v2017071 and v2023011 during transition years
   2. Mandatory adoption of v2023011 by January 1, 2028
   3. Consistent use of RxNorm for medication normalization
   4. Expanded support for advanced transactions (change, cancel, medication history, EPCS)

   ePrescribing can no longer be treated as a static module. It becomes the foundation for RTPB and ePA workflows, requiring careful orchestration and data governance to operate reliably at scale.

2. RTPB: Real-Time Data Requires Real-Time Operations

   HTI-4 formally embeds RTPB into certification requirements. However, RTPB success depends far more on operational reliability than on UI design.

   Vendors must manage:

   1. Real-time payer and PBM queries
   2. Patient-specific cost and formulary indicators
   3. Timeout handling, retries, and fallback logic

   Without strong integration operations, RTPB failures surface as workflow disruptions and provider frustration.

3. ePA via FHIR and Da Vinci Implementation Guides

   HTI-4 replaces fragmented prior authorization processes with standardized, FHIR-based workflows.

   Vendors must support:

   1. CRD (Coverage Requirements Discovery)
   2. DTR (Documentation Templates and Rules)
   3. PAS (Prior Authorization Support)

   These are multi-step, stateful workflows that require orchestration, document handling, and payer variability management. Partial or siloed implementations often fail in production.

4. Certified APIs Are Now Mandatory

   HTI-4 strengthens API expectations under the Cures Act framework.

   Vendor responsibilities include:

   1. FHIR R4/R5 APIs
   2. SMART-on-FHIR security profiles
   3. OAuth 2.0, TLS, and API governance
   4. Developer documentation and sandbox environments

   APIs must be certifiable, performant, and governed, not simply exposed.

5. Data Standards as an Automation Enabler

   HTI-4 reinforces consistent use of national vocabularies and FHIR profiles, including RxNorm, LOINC, ICD-10, CPT/HCPCS, SNOMED CT, US Core, Da Vinci, and CARIN.

   Standardization reduces long-term complexity, but only when paired with strong data normalization and governance.

2026–2027: The Hidden Risk of the Transition Years

One of the most underestimated HTI-4 challenges is the transition period itself.

During 2026–2027, vendors must operate:

1. Dual SCRIPT versions
2. Hybrid RTPB and ePA workflows
3. Mixed payer readiness levels

These hybrid states increase error rates, retries, and support volume. Without strong operational visibility, failures surface only as customer escalations or certification findings, when remediation is most expensive.

Operational Readiness Under HTI-4: What Vendors Must Know

Under HTI-4, interoperability maturity is measurable. Vendors operating at scale should be able to answer:

1. RTPB success rates by payer and PBM
2. End-to-end ePA cycle times
3. SCRIPT transaction error rates during dual-version support
4. API latency, timeout trends, and throughput behavior
5. Interfaces with sustained backlogs or inactivity

The ability to answer these questions reflects operational control—not just technical capability.

The Real Risk: Treating HTI-4 as a Compliance Project

Vendors that approach HTI-4 as a checklist often experience:

1. Fragile payer integrations
2. Rework during audits
3. Performance issues at scale
4. Increased implementation friction for customers

HTI-4 rewards vendors that invest early in interoperability-first platform design and operations.

How KPi-Tech Helps Health IT Vendors Operationalize HTI-4 Interoperability

At KPi-Tech, interoperability is not treated as a one-time integration exercise. Through our InterfaceOps interoperability services, we help health IT vendors design, implement, and operate HTI-4–ready integration ecosystems that scale across payers, PBMs, and provider environments.

Our work spans the full interoperability lifecycle, covering RTPB, ePA, updated SCRIPT standards, and certified FHIR APIs while accounting for real world variability across payer endpoints and transition year complexity.

A key differentiator of our InterfaceOps approach is built-in operational observability dashboard. Rather than delivering integrations and relying on reactive support, we embed monitoring and governance directly into how interoperability is delivered and managed.

This enables vendor teams to maintain visibility into:

1. Reliability of RTPB and ePA workflows across payer connections
2. SCRIPT transaction behavior during dual-version transition periods
3. Interface throughput, backlogs, and recurring error patterns
4. API performance trends that affect certification and customer experience

Because this visibility is integrated into the service—not bolted on—it allows interoperability to be operated as a predictable, auditable product capability, rather than a fragile collection of custom connections.

For vendors navigating HTI-4 timelines, especially during the 2026–2027 transition years, this operational rigor reduces risk, shortens resolution cycles, and supports sustained ONC certification without disrupting provider workflows.

Final Thought

HTI-4 makes one thing clear for health IT vendors: interoperability is no longer optional or deferred, it is a core product requirement.

More importantly, HTI-4 establishes a baseline. Future ONC updates, including HTI-5, are expected to continue this shift toward operational, real-world interoperability, where platforms are evaluated not just on supported standards, but on how reliably they function at scale.

Vendors that treat HTI-4 as a checkbox may meet near-term requirements. Those that invest now in scalable, observable interoperability will be better positioned for HTI-4, and whatever comes next.

With InterfaceOps, KPi-Tech helps vendors turn today’s compliance demands into future-ready interoperability capabilities.