The official HL7 FHIR SDK in .NET  

Drive health interoperability and save precious development time with Firely’s open-source FHIR SDK 

FHIR API illustration

Get a running start in implementing FHIR the right way 

Fully compliant to the latest HL7 FHIR standard

Firely is the original author and main contributor of the official HL7 FHIR reference implementation for Microsoft .NET.

Speed up implementation time

Download the NuGet packages of the SDK and you’ll have your first FHIR client running within an hour.

Open-source and trustworthy SDK

The open source library has been downloaded millions of times by developers around the world.

Lower the amount of coding for your team

Build your own FHIR client, server or add-on without having to implement all the basic and advanced FHIR features from scratch.

Key features

Unleash the power of your data 

// Find patients named Eve

var client = new FhirClient("");
Bundle results = await client.SearchAsync<Patient>(new string[] { "family:exact=Eve" });
// Just get the first patient

var pat_A = result.Entry[0].Resource as Patient;
// Add a name to the patient, and update

pat_A.Name.Add(new HumanName().WithGiven("Christopher").AndFamily("Brown"));
var updated_pat = client.Update(pat_A);

  • Serialization and deserialization to XML and JSON  
  • Snapshot generation, validation and caching 
  • Set up complex resource resolving scenarios  

Bring into play for Interoperability and Patient Access Rules

ONC Cures Act

Achieve stress-free compliance with
our FHIR Server, FHIR SDK and FHIR
training courses.

CMS Final Rule

Implement a Patient Access API or
your FHIR API-based Provider
Directory with Firely.

Trusted by leading companies and thousands of developers

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UCSF Customer logo
Data for life customer logo
medcom customer logo

Want to know more about the Firely .NET SDK? 

Get in touch for more information. 

Check out more products from our FHIR suite 


Easily run R scripts against your FHIR server for powerful research and analytics 

Firely Terminal

Build automation pipelines with our cross-platform Command Line Tool for FHIR.


Test your FHIR Server and guarantee high-quality performance, one release after another

Find out how Firely can help you bring FHIR to life

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