# ImATeapotException

**Kind:** Class

**Source:** [`packages/common/exceptions/im-a-teapot.exception.ts`](https://github.com/nestjs/nest/blob/master/packages/common/exceptions/im-a-teapot.exception.ts#L14)

**Part of:** [Common](subsystem-packages-common)

Defines an HTTP exception for *ImATeapotException* type errors.

Any attempt to brew coffee with a teapot should result in the error code
"418 I'm a teapot". The resulting entity body MAY be short and stout.

`ImATeapotException` represents the HTTP `418 I'm a Teapot` response defined for requests that cannot be fulfilled because a teapot was asked to brew coffee. It extends the framework’s HTTP exception system so controllers, guards, or services can return a consistent status code and response body for this intentionally humorous but standardized error case.

**Extends:** `HttpException`

## Diagram

```mermaid
graph LR
  A[Incoming HTTP Request] --> B{Request asks teapot<br/>to brew coffee?}
  B -- Yes --> C[Throw ImATeapotException]
  C --> D[HTTP Exception Handler]
  D --> E[418 I'm a Teapot Response]
  B -- No --> F[Continue normal processing]
```

## Usage

```ts
import { Controller, Get } from '@nestjs/common';
import { ImATeapotException } from '@nestjs/common';

@Controller('coffee')
export class CoffeeController {
  @Get('brew')
  brewCoffee() {
    const appliance = 'teapot';

    if (appliance === 'teapot') {
      throw new ImATeapotException(
        'A teapot cannot brew coffee. The response body may be short and stout.',
      );
    }

    return { status: 'brewing' };
  }
}
```

## AI Coding Instructions

- Throw `ImATeapotException` only when the intended HTTP response is `418 I'm a Teapot`.
- Provide a concise response message or body when useful; callers may rely on the exception’s standard HTTP status code.
- Prefer framework exception handling over manually constructing a `Response` with status `418`.
- Use this exception in controllers or service-layer validation paths where the request is semantically inappropriate, not for general client errors.