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

# Responses

> Returning JSON responses and HTTP status codes from BackAnt routes.

All BackAnt routes return JSON using Flask's `jsonify()` function.

## Basic JSON response

```python theme={null}
from flask import jsonify

@users_bp.get("")
def get_users():
    response = myUsersService.get_users()
    return jsonify(response)
```

`jsonify()` accepts dicts, lists, strings, numbers, booleans, and `None`. It sets the `Content-Type` header to `application/json` automatically.

## Returning SQLAlchemy models

SQLAlchemy models in BackAnt are `@dataclass` classes, which means they serialize to dicts automatically when passed to `jsonify()`:

```python theme={null}
@dataclass
class Users(Base):
    __tablename__ = "users"
    id: int = Column(Integer, primary_key=True)
    name: str = Column(String)
```

```python theme={null}
user = myUsersRepository.get_by_id(1)
return jsonify(user)
# {"id": 1, "name": "Alice"}
```

For lists of models:

```python theme={null}
users = myUsersRepository.get_all_users()
return jsonify(users)
# [{"id": 1, "name": "Alice"}, {"id": 2, "name": "Bob"}]
```

## HTTP status codes

Pass the status code as the second return value:

```python theme={null}
return jsonify(response), 200   # OK (default)
return jsonify(response), 201   # Created
return jsonify({}), 204         # No Content
return jsonify(response), 400   # Bad Request
return jsonify(response), 404   # Not Found
```

## Error responses

Do not construct error responses manually in routes. Raise `APIException` from the service layer and the registered error handler in `app.py` converts it to JSON automatically:

```python theme={null}
# In the service:
raise APIException(status_code=404, message="User not found")

# Automatically becomes:
# HTTP 404
# {"message": "User not found"}
```

See [Error Handling](/the-basics/error-handling) for the full `APIException` API.

## Adding response headers

```python theme={null}
response = jsonify(data)
response.headers["X-Total-Count"] = str(total)
return response
```

## Returning empty responses

For `DELETE` endpoints that return no body:

```python theme={null}
return jsonify({}), 204
```

Or with a confirmation message:

```python theme={null}
return jsonify({"deleted": True, "id": user_id}), 200
```