How-To: Use Custom Schemas and Aliases

Use a custom schema when you need explicit validation, aliases, or read/write field control. If you omit schema on a view, FastAPI-Restly generates one automatically from the model — this guide covers the cases where you want full control instead.

1. Define Model

import fastapi_restly as fr
from sqlalchemy.orm import Mapped

class User(fr.IDBase):
    first_name: Mapped[str]
    email: Mapped[str]
    password_hash: Mapped[str]

2. Define Schema

from pydantic import Field
import fastapi_restly as fr

class UserSchema(fr.IDSchema):
    # Alias: clients send "firstName", the ORM field is "first_name"
    first_name: str = Field(alias="firstName")
    email: str
    # WriteOnly: accepted on POST/PATCH but never included in responses
    password_hash: fr.WriteOnly[str]

IDSchema already provides an id field marked fr.ReadOnly, so id is automatically excluded from POST and PATCH payloads — you do not need to declare it yourself.

fr.WriteOnly[T] marks a field as write-only: it is accepted in create and update requests but stripped from all responses.

3. Attach Schema to View

@fr.include_view(app)
class UserView(fr.AsyncRestView):
    prefix = "/users"
    model = User
    schema = UserSchema

What You Get

• Incoming payloads accept the alias key (firstName).

• Responses use the alias key (firstName) on Restly routes as well.

• id never appears in POST/PATCH request bodies because it is ReadOnly on IDSchema.

• password_hash never appears in responses because it is WriteOnly.