FHIR Overview

A Guide to Modern Healthcare Interoperability

FHIR, which stands for Fast Healthcare Interoperability Resources, is a modern standard developed by HL7 to simplify how healthcare systems exchange data electronically. It was created to solve long-standing challenges in healthcare interoperability, replacing complex message formats with web-friendly, standardized resources that are easier for developers to work with.

FHIR has become the foundation for interoperability initiatives across healthcare. Major EHR vendors, HIEs, and health technology companies use it to securely share patient information and power new applications.

What is FHIR and Why It Matters

FHIR was created to make it easier for healthcare organizations to share clinical data in a consistent, secure way. It builds on established web technologies like REST APIs, JSON, and XML, making it accessible to both traditional healthcare IT teams and modern software developers.

Unlike earlier HL7 standards such as v2 or CDA, which rely on rigid message formats, FHIR organizes data into modular pieces called resources. These resources represent real-world healthcare concepts like patients, lab results, and encounters. Each resource is self-contained, extensible, and can be easily exchanged through standard web requests.

Learn more: What is FHIR and Why It Matters

How FHIR Works

At its core, FHIR uses a RESTful API approach that allows applications to read, create, update, or delete healthcare data using simple web operations. This structure makes integration far easier than traditional HL7 interfaces.

Each piece of clinical information is represented as a FHIR resource. For example, a patient record might look like this:

{
  "resourceType": "Patient",
  "id": "12345",
  "name": [{ "family": "Doe", "given": ["Jane"] }],
  "gender": "female",
  "birthDate": "1990-05-02"
}

A client can retrieve this resource by calling a FHIR endpoint such as:

GET https://example-hospital.org/fhir/Patient/12345

FHIR also supports batch operations, search parameters, and references between related resources.

Learn more: How FHIR Works

FHIR's Core Building Blocks: Resources and Data Models

FHIR organizes data into resources. Each resource defines a specific type of healthcare information, such as:

• Patient: demographic and identifying details
• Observation: lab results, vitals, or other findings
• Encounter: details about visits or care episodes
• Practitioner: information about clinicians
• Medication: prescribed or administered drugs

Resources can reference one another, forming a connected web of data. For example, a Patient may be linked to multiple Encounter and Observation records.

Learn more: FHIR Resources Overview

FHIR APIs and Integration

FHIR's strength comes from its ability to be implemented as a web API. Systems can expose REST endpoints such as /Patient or /Observation that allow other systems or applications to access standardized data.

This model supports real-time interoperability between EHRs, patient apps, and analytics systems. Security standards like OAuth2 and SMART on FHIR help ensure that sensitive data is shared safely and with proper authorization.

In real-world environments, exchanging FHIR data reliably requires an integration engine that can connect APIs, validate messages, and manage transformations between formats. Iguana makes this possible by enabling healthcare teams to:

• Handle FHIR requests and responses with Lua-based scripting
• Transform between HL7 v2 and FHIR JSON
• Monitor and manage FHIR message flows
• Combine FHIR APIs with existing integration workflows

Learn more: The FHIR API and How it Works

Extending FHIR: Profiles and Customization

FHIR provides a strong foundation, but every healthcare organization has unique needs. To support flexibility, FHIR allows Profiles and Extensions that customize standard resources. These tools help define specific data constraints, add fields, or enforce required values.

Profiles ensure that systems follow consistent rules when sharing customized FHIR data. For example, a local lab might define a custom Observation profile that specifies required units for blood glucose measurements.

Did you know?

• Iguana's FHIR Profiling Tool makes it easy to create and validate FHIR profiles within your integration environment.
• Iguana's FHIR Resource Creator allows you to programmatically generate valid FHIR resources from HL7 messages, databases, or APIs.

Learn more: FHIR Profiles and Extensions

Why FHIR Adoption is Accelerating

Regulatory initiatives and patient-centered healthcare delivery are driving FHIR’s adoption at scale. Key factors include:

• The 21st Century Cures Act, which requires APIs for patient data access
• Broad support from major EHR vendors like Epic, Cerner, and Athenahealth
• The rise of SMART on FHIR apps that empower patients and providers
• The need for real-time, interoperable data across care settings

FHIR has become the common language for connecting healthcare systems, enabling innovation while improving care coordination.

How Iguana Fits into the FHIR Ecosystem

As healthcare organizations adopt FHIR, they face new integration challenges: bridging older HL7 v2 interfaces, ensuring validation, and managing high message volumes.

Iguana is designed to handle these exact needs. It serves as a flexible, enterprise-grade integration platform that can:

• Transform HL7 v2 messages into FHIR JSON resources
• Exchange data with FHIR APIs securely
• Manage hybrid interoperability across FHIR, REST, and file-based systems
• Provide monitoring, error handling, and scalability for production environments

By combining educational value with hands-on practicality, Iguana helps healthcare teams move from understanding FHIR to implementing it successfully.

Learn more: FHIR API Integration in Iguana

Learn More about FHIR