We sought to enable better interoperability and easy adoption of healthcare applications by developing a standardized domain independent Application Programming Interface (API) for an Electronic Medical Record (EMR) system. We leveraged the modular architecture of the Open Medical Record System (OpenMRS) to build a Fast Healthcare Interoperability Resources (FHIR) based add-on module that could consume FHIR resources and requests made on OpenMRS. The OpenMRS FHIR module supports a subset of FHIR resources that could be used to interact with clinical data persisted in OpenMRS. We demonstrate the ease of connecting healthcare applications using the FHIR API by integrating a third party Substitutable Medical Apps & Reusable Technology (SMART) application with OpenMRS via FHIR. The OpenMRS FHIR module is an optional component of the OpenMRS platform. The FHIR API significantly reduces the effort required to implement OpenMRS by preventing developers from having to learn or work with a domain specific OpenMRS API. We propose an integration pathway where the domain specific legacy OpenMRS API is gradually retired in favor of the new FHIR API, which would be integrated into the core OpenMRS platform. Our efforts indicate that a domain independent API is a reality for any EMR system. These efforts demonstrate the adoption of an emerging FHIR standard that is seen as a replacement for both Health Level 7 (HL7) Version 2 and Version 3. We propose a gradual integration approach where our FHIR API becomes the preferred method for communicating with the OpenMRS platform.