---
title: Models Overview
description: Overview of ArchiPy domain model layer including entities, DTOs, errors, and types.
---

# Models

The `models` module contains the domain layer data structures — entities, DTOs, errors, and types. This layer holds no
business logic or I/O; it defines only the shapes of data flowing through the application.

## Submodules

| Submodule               | Description                                         |
|-------------------------|-----------------------------------------------------|
| [DTOs](dtos.md)         | Pydantic data transfer objects for API input/output |
| [Entities](entities.md) | SQLAlchemy ORM entity base classes                  |
| [Errors](errors.md)     | Custom exception hierarchy                          |
| [Types](types.md)       | Enumerations and shared type definitions            |

## Source Code

📁 Location: `archipy/models/`

🔗 [Browse Source](https://github.com/SyntaxArc/ArchiPy/tree/master/archipy/models)

## API Stability

| Component | Status    | Notes            |
|-----------|-----------|------------------|
| DTOs      | 🟢 Stable | Production-ready |
| Entities  | 🟢 Stable | Production-ready |
| Errors    | 🟢 Stable | Production-ready |
| Types     | 🟢 Stable | Production-ready |
