FHIR Core Library

1.1.7 · active · verified Mon Apr 13

fhir-core is a Python library providing an abstract base class for FHIR resource models and Primitive Datatypes, along with factories to create FHIR resource models and other complex datatypes. It is powered by Pydantic V2, ensuring data validation and efficient serialization/deserialization. This library is primarily developed to support the 'fhir.resources' library but can be used independently. As of March 2026, the current version is 1.1.7, with frequent patch releases.

Warnings

breaking Between fhir-core 0.x and 1.x (and consequently fhir.resources <8.0.0 and >=8.0.0), there were significant breaking changes in the base model class and its methods. `FHIRAbstractBase` was replaced by `FHIRAbstractModel`. Methods like `__init__`, `parse_obj`, `as_json`, and `dict` had their signatures or behavior altered.
Fix: Update your code to use `FHIRAbstractModel` as the base class. Review and adapt calls to `parse_obj` (now a classmethod), and prefer `model_dump()` or `model_dump_json()` from Pydantic V2 for serialization instead of `as_json` or `dict`.
gotcha fhir-core is developed by 'nazrulworld'. Be aware that other Python libraries with similar names exist (e.g., `google-fhir-core`, `fhir-py`, `fhirclient`), which serve different purposes or are maintained by different entities. Ensure you are importing from `fhir_core` (with an underscore).
Fix: Always verify the `pypi-slug` and `source_url` to confirm you are using the correct library. Use `pip install fhir-core` for this specific library.
breaking fhir-core relies on Pydantic V2. If your project uses Pydantic V1, there will be incompatibilities. Ensure your environment is set up with Pydantic V2 or later.
Fix: Upgrade Pydantic to version 2 or greater (`pip install 'pydantic>=2'`). Review Pydantic V1 to V2 migration guides if you have existing Pydantic models.
breaking The `fhir.resources` library, which `fhir-core` supports, has minimum version requirements for `fhir-core`. For instance, `fhir.resources` 8.0.0 requires `fhir-core` 1.0.0, and `fhir.resources` 8.2.0 requires `fhir-core` 1.1.5. Incompatible versions between the two libraries can lead to runtime errors.
Fix: Always ensure that the `fhir-core` version installed meets or exceeds the minimum requirement specified by your `fhir.resources` version. Check the release notes or `install_requires` of `fhir.resources` for compatibility.

Install

pip install fhir-core Install stable version
git clone https://github.com/nazrulworld/fhir-core.git && cd fhir-core && pip install -e .[dev] Install development version

Imports

FHIRAbstractModel

from fhir_core.fhirabstractmodel import FHIRAbstractModel

IdType
```
from fhir_core.types import IdType
```
BooleanType
```
from fhir_core.types import BooleanType
```
StringType
```
from fhir_core.types import StringType
```

Quickstart

This example demonstrates how to define a simple FHIR 'Organization' model inheriting from `FHIRAbstractModel` and populate it with data. It showcases the use of `fhir_core.types` for primitive FHIR data types and Pydantic's `Field` for alias and validation.

from typing import List
from pydantic import Field
from fhir_core.fhirabstractmodel import FHIRAbstractModel
from fhir_core.types import IdType, BooleanType, StringType

class Organization(FHIRAbstractModel):
    resourceType: StringType = Field('Organization', const=True)
    id: IdType = Field(None, alias='id')
    active: BooleanType = Field(None, alias='active')
    name: StringType = Field(None, alias='name')
    address: List[dict] = Field(None, alias='address') # Simplified for example

data = {
    "id": "f001",
    "active": True,
    "name": "Acme Corporation",
    "address": [
        {
            "use": "work",
            "line": ["534 Erewhon St"],
            "city": "PleasantVille",
            "state": "Vic",
            "postalCode": "3999",
            "country": "ZZ"
        }
    ]
}

organization_instance = Organization(**data)

print(organization_instance.json(indent=2))

view raw JSON →