> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usebruno.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Assertions

Assertions allow you to declaratively write tests without writing any code.

## Getting Started

1. Open a request and click on the **Assert** tab
2. Add assertions by specifying:
   * **Expression**: The value to test (e.g., `res.status`, `res.body.id`)
   * **Operator**: The comparison operator
   * **Value**: The expected value

<img src="https://mintcdn.com/bruno-a6972042/K-YsMv4Crp6p2uFR/images/screenshots/get-started/bruno-basics/create_test/bru_test_assert.webp?fit=max&auto=format&n=K-YsMv4Crp6p2uFR&q=85&s=1db45ae9758d83d055d41d7c2d69ec40" alt="bru assertions" width="2480" height="1046" data-path="images/screenshots/get-started/bruno-basics/create_test/bru_test_assert.webp" />

## Common Examples

### Basic Response Testing

| Expression | Operator | Value |
| - | - | - |
| `res.status` | `equals` | `200` |
| `res.body.status` | `equals` | `success` |
| `res.body.message` | `contains` | `created` |
| `res.body.id` | `isNotEmpty` | |

### Nested Objects

```json theme={null}
{
  "user": {
    "profile": {
      "name": "John",
      "email": "john@example.com"
    }
  }
}
```

| Expression | Operator | Value |
| - | - | - |
| `res.body.user.profile.name` | `equals` | `John` |
| `res.body.user.profile.email` | `contains` | `@example.com` |

### Arrays

```json theme={null}
{
  "users": [
    { "id": 1, "name": "Alice" },
    { "id": 2, "name": "Bob" }
  ]
}
```

| Expression | Operator | Value |
| - | - | - |
| `res.body.users` | `isNotEmpty` | |
| `res.body.users[0].name` | `equals` | `Alice` |
| `res.body.users[1].id` | `equals` | `2` |

### Using res() Query

For complex nested data, use the `res()` function:

```json theme={null}
{
  "order": {
    "items": [
      { "id": 1, "price": 29.99 },
      { "id": 2, "price": 69.99 }
    ]
  }
}
```

| Expression | Operator | Value |
| - | - | - |
| `res('order.items[0].price')` | `equals` | `29.99` |
| `res('..price')` | `isNotEmpty` | |

Learn more about `res()` in [Response Query](../script/response/response-query) docs.

### Response Headers

| Expression | Operator | Value |
| - | - | - |
| `res.headers['content-type']` | `contains` | `application/json` |

### Response Time

| Expression | Operator | Value |
| - | - | - |
| `res.responseTime` | `lt` | `1000` |

## Available Operators

* **Comparison**: `equals`, `notEquals`, `gt`, `gte`, `lt`, `lte`
* **String**: `contains`, `notContains`, `startsWith`, `endsWith`, `matches`, `notMatches`
* **Type Checks**: `isNull`, `isNotEmpty`, `isEmpty`, `isDefined`, `isUndefined`
* **Value Checks**: `isTruthy`, `isFalsy`, `isNumber`, `isString`, `isBoolean`, `isArray`, `isJson`
* **Other**: `in`, `notIn`, `between`, `length`

## Advanced Testing

For complex test scenarios with custom logic, use [Test Scripts](./introduction) with JavaScript and Chai assertions.