# API reference

If you're looking for technical API details, you've come to the right place.

- Read through our FHIR specs, which contain schemas for:
  - [FHIR resources](https://docs.redoxengine.com/permalink/fhir-resources-landing-page)
  - [FHIR notifications](https://docs.redoxengine.com/permalink/fhir-notification-landing-page)
- [Review data model specs](https://docs.redoxengine.com/permalink/data-model-landing-page) with notes for what to expect when using each data model.
- [Use Platform API endpoints](https://docs.redoxengine.com/permalink/platform-api-landing-page) to manage your Redox organization via API. 
_The Platform API requires user-level API keys instead of OAuth API keys._

In this section, you'll also find information about:

- [OAuth API key authentication](/api-reference/redox-data-model-api/authenticate-an-oauth-api-key)
- [error handling](/api-reference/error-handling-and-responses)
- [quotas and constraints](/api-reference/quotas-and-constraints)

## Community tools

Explore tools created by customers within our Redox community.

[Learn more](/api-reference/community-tools)

## Product Changelog

Keep up with new features and updates to Redox products.

[Learn more](https://www.redoxengine.com/blog/category/redox/changelog/)

## Popular articles

### Authenticate with OAuth

Learn how to authenticate your API requests with an OAuth API key.

[Learn more](/api-reference/redox-data-model-api/authenticate-an-oauth-api-key)

### Authenticate Platform APIs

Authenticate your Platform API requests with user-level API keys. Check out our step-by-step guide.

[Learn more](/api-reference/platform-api/authenticate-a-user-level-api-key)

### Download dev tools

Explore Redox APIs with developer test tools.

[Learn more](/how-to-use-redox/use-developer-test-tools)

## Articles in this section

Dive into technical specs to code up to Redox and exchange data with your connections.

- [Error handling and responses](/api-reference/error-handling-and-responses)
- [Quotas and constraints](/api-reference/quotas-and-constraints)
- [Community tools](/api-reference/community-tools)

## [FHIR® API](/api-reference/fhir-api-reference)

FHIR API resources and notifications.

- [Authenticate an OAuth API key](/api-reference/redox-data-model-api/authenticate-an-oauth-api-key)

## [Redox Data Model API](/api-reference/redox-data-model-api)

- [Authenticate an OAuth API key](/api-reference/redox-data-model-api/authenticate-an-oauth-api-key)
- [Event types for data models](/api-reference/redox-data-model-api/event-types-for-data-models)
- [Extensions for data models](/api-reference/redox-data-model-api/extensions-for-data-models)

## [Platform API](/api-reference/platform-api)

- [Authenticate a user-level API key](/api-reference/platform-api/authenticate-a-user-level-api-key)