# POST /api/v1/budgets/{budget_id}/activate

> Activate budget

- **Tag:** budgets
- **Operation ID:** `activate_budget_api_v1_budgets__budget_id__activate_post`

## Description

Set a budget as the active budget (deactivates current active).

## Authentication

Bearer token in `Authorization` header.
Required header: `x-business-id: <business uuid>`.

## Parameters

- `budget_id` (path, string, required)

## Responses

### 201 — Successful Response

Schema: `BudgetResponse`

- `id` (string · required) — Budget UUID.
- `name` (string · required) — Budget name.
- `fiscal_year` (integer · required) — Fiscal year.
- `start_date` (string · date · required) — Budget period start date.
- `end_date` (string · date · required) — Budget period end date.
- `status` (BudgetStatusEnum · required) → `BudgetStatusEnum` — Budget status: draft, active, or closed.
- `period_type` (BudgetPeriodTypeEnum · required) → `BudgetPeriodTypeEnum` — Period granularity.
- `description` (string) — Budget description.
- `notes` (string) — Additional notes.
- `line_count` (integer) — Number of budget lines.
- `total_budgeted_revenue` (integer) — Total budgeted revenue in cents.
- `total_budgeted_expenses` (integer) — Total budgeted expenses in cents.
- `budgeted_net_income` (integer) — Budgeted net income (revenue - expenses) in cents.
- `source_scenario_id` (string) — CFO projection scenario UUID that generated this budget.
- `business_id` (string · required) — Business UUID.
- `created_at` (string · date-time · required) — Creation timestamp.
- `updated_at` (string · date-time · required) — Last update timestamp.

### 400 — Bad Request - Invalid input

### 401 — Unauthorized - Authentication required

### 403 — Forbidden - Insufficient permissions

### 404 — Not Found - Resource does not exist

### 422 — Validation Error

Schema: `HTTPValidationError`

- `detail` (array · ValidationError) → `ValidationError`
  - `loc` (array · string | integer · required)
  - `msg` (string · required)
  - `type` (string · required)
  - `input` (object)
  - `ctx` (object)

## Code samples

### cURL

```bash
curl -X POST 'https://api.ondayzero.com/api/v1/budgets/{budget_id}/activate' \
  -H 'Authorization: Bearer dz_your_token' \
  -H 'x-business-id: YOUR_BUSINESS_ID'
```

### JavaScript

```javascript
const response = await fetch('https://api.ondayzero.com/api/v1/budgets/{budget_id}/activate', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer dz_your_token',
    'x-business-id': 'YOUR_BUSINESS_ID',
  },
});
const data = await response.json();
```

### Python

```python
import httpx

headers = {
    "Authorization": "Bearer dz_your_token",
    "x-business-id": "YOUR_BUSINESS_ID",
}

response = httpx.post("https://api.ondayzero.com/api/v1/budgets/{budget_id}/activate", headers=headers)
data = response.json()
```

## See also

- HTML version: https://www.ondayzero.com/docs/reference/budgets/activate-budget
- OpenAPI slice: https://www.ondayzero.com/docs/reference/budgets/activate-budget/openapi.json
- Other endpoints in **budgets**: https://www.ondayzero.com/docs/reference/budgets