# Bad Request (BAD_REQUEST)

The request was invalid. The response body typically contains specific error
details explaining what went wrong.

## Common causes

- **Malformed JSON body** - The request body contains invalid JSON, such as
  missing commas, unclosed brackets, or trailing commas.
- **Missing required fields** - The request is missing one or more fields that
  the API expects.
- **Invalid Content-Type header** - The `Content-Type` header does not match the
  format of the request body. For example, sending JSON without setting
  `Content-Type: application/json`.
- **Invalid parameter types** - A field value does not match the expected type,
  such as sending a string where a number is required.

## How to debug

1. Check the response body for specific error messages. Zuplo returns detailed
   error information that identifies the exact issue.
2. Validate the request body using a JSON linter or validator before sending.
3. Verify that all required headers are present and correctly formatted.
4. Compare the request against the API documentation to ensure all required
   fields are included with the correct types.

:::tip

Use a tool like `curl -v` or an API client such as Postman to inspect the full
request and response, including headers and body.

:::

## Related errors

If the request body fails JSON Schema validation, see
[Schema Validation Failed](./schema-validation-failed.mdx) for more details.