# Domain model
URL: https://docs.awellhealth.com/api-reference/guides/domain-model

> For the complete documentation index, see [llms.txt](https://docs.awellhealth.com/llms.txt).



Every interaction with Awell Orchestration goes through the API. This page is the mental model the rest
of the reference assumes. **Read it before the activity queries**, which are hard to use without it.

## A typical lifecycle [#a-typical-lifecycle]

1. **Create a patient.** Nothing else can happen first, because every care flow belongs to a patient.
   See [Patients](/api-reference/reference/patients).
2. **Start a care flow** for that patient. See [Start a care flow](/api-reference/guides/start-a-care-flow).
3. **Get the pending activities** for that care flow. See
   [Query activities](/api-reference/guides/query-activities).
4. **Request the details** of the next activity, for example a form's questions.
5. **Complete the activity**, for example by submitting a form response. See
   [Work with forms](/api-reference/guides/work-with-forms).

Then repeat from step 3: an integration is a loop over activities rather than a linear script.

## Definitions and instances [#definitions-and-instances]

The API separates designs from instances:

* A **care flow definition** is the template designed in Studio.
* A **care flow** is one patient's instance of it.
* A **data point definition** is a field in the design; a **data point** is one patient's value.

Query definitions to ask about your design; query care flows and data points to ask about patients. See
[Versions and releases](/api-reference/guides/versions-and-releases) for why a definition's version
matters.

## Activities are the unit of work [#activities-are-the-unit-of-work]

An **activity** is one thing to be done or that happened. Activities cover more than user tasks: track
activations, step completions and reminders are activities too, so the activity list is the full history
of a care flow rather than a to-do list.

Consequences for an integration:

* **Expect system activities** you didn't ask for, and filter rather than assuming everything is a task.
* **Expect repetition.** A looping track produces the same step's activity many times for one patient.

## Why GraphQL [#why-graphql]

Awell chose GraphQL as the primary programmatic interface:

* **You query only what you need**, which keeps responses small.
* **Types and schemas** mean client libraries can consume the API without manual parsing.
* **Client independence**: you can change what you request without waiting for a new endpoint.

## Next steps [#next-steps]

**Next:** [Start a care flow](/api-reference/guides/start-a-care-flow).