> For the complete documentation index, see [llms.txt](https://docs.abtasty.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.abtasty.com/server-side/command-line-interface/resource-loader/feature-experimentation/flag.md).

# Flag

Schema, including its fields, nested structure, and relationships

#### Definition

A **Flag** is a governed feature toggle/config key your application reads at runtime. Variations set flag values via **modifications** (e.g., `"type": "FLAG"` in a variation). Declaring flags centrally enforces naming, typing, and reuse across campaigns.

#### Payload Properties

When creating or updating a flag, the `payload` can include:

* **`id`** (String, *optional*) – The flag's unique ID. Include this only when updating an existing flag.
* `name` (String, **required**) — Unique flag key used in `modifications.value`.
* `type` (String, **required**) — Expected value type (e.g., `"string"`, `"boolean"`, `"number"`, `"json"`).
* `description` (String, optional) — Human-readable description.
* `source` (String, optional) — Origin of the flag (e.g., `"manual"`, `"api"`).
* `default_value` (Any, optional) — Default value returned when no override/experiment applies.
* `predefined_values` (Array, optional) — Allowed values (for enums or UI pickers). Leave empty for free-form types.

> Notes\
> • Keep `type` consistent with the values you plan to set in variations.\
> • Use `predefined_values` to constrain inputs (e.g., `["blue","green"]`) when you want UI validation.

**Example Project Payload:**

```json
{
  "name": "flag_created_with_resource_loader",
  "type": "string",
  "description": "Loaded from resource loader",
  "source": "manual",
  "default_value": "",
  "predefined_values": []
}
```

#### Response Fields

When a Flag is returned by the API/Resource Loader, you’ll receive server-managed metadata plus the normalized definition:

* `id` (String) — Unique flag identifier.
* `name` (String) — Flag key.
* `type` (String) — Value type (e.g., `"string"`).
* `description` (String) — Description.
* `source` (String) — Origin (e.g., `"manual"`).
* `default_value` (Any) — Default value when no overrides apply.
* `predefined_values` (Array) — Allowed values, if any.
* `created_at` (String, ISO-8601) — Creation timestamp.

**Example Response**

```json
{
  "created_at": "2025-11-12T11:26:43+00:00",
  "default_value": "",
  "description": "Loaded from resource loader",
  "id": "flag_id",
  "name": "flag_created_with_resource_loader",
  "predefined_values": [],
  "source": "manual",
  "type": "string"
}
```

#### Error Codes

* **InvalidPayload** – Missing project name when creating a project, or other payload formatting issues.
* **PermissionDenied** – User not allowed to create projects (if such permission is restricted).


---

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