HAPI FHIR: Connecting Interoperability dots for Healthcare

Open source and proprietary are the two types of FHIR servers. The Open-source FHIR server is free to use.

It provides all the basic features to develop custom solutions. The most famous open FHIR is the HAPI FHIR server. Let’s dig deeper into what is HAPI FHIR.

Introduction to HAPI FHIR

It is an implementation of the HL7 FHIR specification for Java. To get a quick peek into what is FHIR, click here. The FHIR specification is designed to be legible and implementable. 

FHIR is a good specification because it is molded based on the design of other successful APIs like Highrise API. HAPI FHIR is based on the same concept but applied to Java implementation. HL7 has based the design of this API on the JAXB and JAX-WS APIs, which are very considerable and usable APIs.

But it doesn’t mean that HAPI FHIR uses those two APIs or that HAPI FHIR is compliant with JAXB (JSR222) or JAZ-WS (JSR224). They have just tried to imitate the flexible and easy-to-use designs.

A round-up on FHIR Versions

Before moving on with HAPI, let’s take a quick stop at FHIR versions. FHIR is not yet a concluded “1.0” standard. It is in the DSTU phase. This means that it is changing between releases. Decide which version of FHIR you want to support in your application before using it.

What is HAPI FHIR Server? [A round-up]

As we mentioned earlier, the HAPI FHIR server is an open-source type of FHIR server. It is a full implementation of the HL7 FHIR standard for healthcare interoperability in Java. HAPI is a free community that develops licensed software under Apache Software License 2.0.

It is a product of Smile CDR. HAPI FHIR server offers many features that are available with Proprietary FHIR servers. And being an open source with all these features makes it the most preferable one for FHIR implementation.

How to Download/Import HAPI FHIR?

  • The best way to use HAPI FHIR when you are developing applications in Java is to use a build system that handles dependency management automatically.
  • The two such common systems are Apache Maven and Gradle.
  • These will automatically download “dependency” libraries and add them to your classpath.
  • You can manually download the latest release of HAPI if you are not using one of these systems.


1. Core Libraries

  • hapi-fhir-base: This is the core HAPI FHIR library and is always required to use the framework. It contains the context, parsers, and other support classes.

2. Structures

  • hapi-fhir-structures-dstu2: This module contains FHIR DSTU2 model classes
  • hapi-fhir-structures-hl7org-dstu2: This module contains alternate FHIR DSTU2 model classes. The HAPI FHIR and FHIR “Java Reference Implementation” libraries were merged in 2015, and at the time there were two parallel sets of DSTU2 model classes. This set more closely resembles the model classes for DSTU3+ whereas the other set more closely resembles the original DSTU1 model classes. The two DSTU2 model JARs are functionally identical, but the various utility methods on the classes are somewhat different.
  • hapi-fhir-structures-dstu3: This module contains FHIR DSTU3 model classes.
  • hapi-fhir-structures-r4: This module contains FHIR R4 model classes.
  • hapi-fhir-structures-r5: This module contains FHIR R5 model classes.
  • hapi-fhir-converter: This module contains converters for converting between FHIR versions.
  • hapi-fhir-structures-dstu (retired): This module contained FHIR DSTU1, model classes. It was retired in HAPI FHIR 3.0.0.

3. Client Framework

  • hapi-fhir-client: This module contains the core FHIR client framework, including an HTTP implementation based on Apache HttpClient. It is required to use client functionality in HAPI.
  • hapi-fhir-client-okhttp: This module contains an alternate HTTP implementation based on OKHTTP.
  • hapi-fhir-android: This module contains the Android HAPI FHIR framework, which is an FHIR client framework that has been tailored specifically to run on Android

4. Validation

  • hapi-fhir-validation: This module contains the FHIR Profile Validator, which is used to validate resource instances against FHIR Profiles (StructureDefinitions, ValueSets, CodeSystems, etc.).
  • hapi-fhir-validation-resources-dstu2: This module contains the StructureDefinitions, ValueSets, CodeSystems, Schemas, and Schematrons for FHIR DSTU2
  • hapi-fhir-validation-resources-dstu2.1: This module contains the StructureDefinitions, ValueSets, CodeSystems, Schemas, and Schematrons for FHIR DSTU2.1
  • hapi-fhir-validation-resources-dstu3: This module contains the StructureDefinitions, ValueSets, CodeSystems, Schemas, and Schematrons for FHIR DSTU3
  • hapi-fhir-validation-resources-r4: This module contains the StructureDefinitions, ValueSets, CodeSystems, Schemas, and Schematrons for FHIR R4
  • hapi-fhir-validation-resources-r5: This module contains the StructureDefinitions, ValueSets, and CodeSystems for R5. As of FHIR R5, Schema and Schematron files are no longer distributed with HAPI FHIR.

5. Server

  • hapi-fhir-server: This module contains the HAPI FHIR Server framework, which can be used to develop FHIR-compliant servers against your own data storage layer.
  • hapi-fhir-jpaserver-base: This module contains the HAPI FHIR “JPA Server”, which is a complete FHIR server solution including a database and implementations of many advanced FHIR server features.
  • hapi-fhir-testpage-overlay: This module contains the web-based “testpage overlay”, which is the UI that powers our Public Demo Server and can also be added to your applications.

HL7 FHIR Services from Capminds

CapMinds Technologies offers the perfect all-in-one Health Interoperability solutions for your clinical needs. Our HL7 integration and FHIR services help the innovatory exchange to create new possibilities. Our client-centered services keep them in the limelight. Our clinical integrations have EHR-integrated laboratory, imaging, e-prescriptions, EPCS, pharmacy, and much more. These enhance the activation process for your individual and collective needs.

“CapMinds Technologies is the place that will make you achieve your goals by combining “Expertise+Hardwork+Commitment”.

CapMinds HL7 FHIR APIs services cover your health data with more security, privacy, and confidentiality. We update ourselves with the latest versions like HL7 Version 2, Version 3, FHIR, SMART on FHIR, CDA, X12, Mirthconnect, and security standards. CapMinds offers the best HL7 integration & HL7/FHIR interface development services for the federal government, health tech startups, laboratories, clinics, and practices.

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