Task Manager API

A REST API for managing tasks, built with FastAPI, Pydantic, SQLite, and pytest.

The project demonstrates a complete CRUD workflow:

HTTP request
→ FastAPI endpoint
→ Pydantic validation
→ SQLite database operation
→ response model validation
→ JSON response

Features

• Create tasks
• Read all tasks
• Read a task by ID
• Partially update tasks
• Delete tasks
• Persistent SQLite storage
• Request and response validation with Pydantic
• Automatic interactive API documentation
• Isolated tests using temporary databases

Tech Stack

• Python
• FastAPI
• Pydantic
• SQLite
• Uvicorn
• pytest
• FastAPI TestClient

Project Structure

task-manager-api/
├── data/
│   └── tasks.db
├── src/
│   └── task_manager_api/
│       ├── __init__.py
│       ├── api.py
│       ├── database.py
│       └── models.py
├── tests/
│   ├── conftest.py
│   ├── test_api_post.py
│   ├── test_api_get.py
│   ├── test_api_patch.py
│   ├── test_api_delete.py
│   └── test_database.py
├── pyproject.toml
├── README.md
├── .gitignore
└── requirements.txt

Data Model

A task contains the following fields:

Field	Type	Required	Description
id	integer	generated	Unique identifier created by SQLite
title	string	yes	Non-empty task title
description	string or null	no	Optional task description
due_date	date or null	no	Optional due date in YYYY-MM-DD format

Example:

{
  "id": 1,
  "title": "List of products",
  "description": "Milk, eggs, bread",
  "due_date": "2026-07-12"
}

Installation

Clone the repository and enter the project directory:

git clone https://github.com/herdlich/task-manager-api.git
cd task-manager-api

Create and activate a virtual environment:

python -m venv .venv

Linux and macOS:

source .venv/bin/activate

Windows PowerShell:

.venv\Scripts\Activate.ps1

Install the project and its dependencies declared in pyproject.toml:

pip install -e .

Running the API

Run Uvicorn from the project root:

uvicorn task_manager_api.api:app --reload

The API will be available at:

http://127.0.0.1:8000

Interactive Swagger documentation:

http://127.0.0.1:8000/docs

Alternative ReDoc documentation:

http://127.0.0.1:8000/redoc

API Endpoints

Method	Endpoint	Description	Success status
GET	/health	Check API availability	200
POST	/tasks	Create a task	201
GET	/tasks	Return all tasks	200
GET	/tasks/{task_id}	Return one task	200
PATCH	/tasks/{task_id}	Partially update a task	200
DELETE	/tasks/{task_id}	Delete and return a task	200

A request for a missing task returns:

{
  "detail": "No task found"
}

with status code 404.

Invalid request data returns status code 422.

Usage Examples

Create a task

curl -X POST "http://127.0.0.1:8000/tasks" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "List of products",
    "description": "Milk, eggs, bread",
    "due_date": "2026-07-12"
  }'

Response:

{
  "id": 1,
  "title": "List of products",
  "description": "Milk, eggs, bread",
  "due_date": "2026-07-12"
}

Get all tasks

curl "http://127.0.0.1:8000/tasks"

Get one task

curl "http://127.0.0.1:8000/tasks/1"

Update a task

Only fields included in the request are changed:

curl -X PATCH "http://127.0.0.1:8000/tasks/1" \
  -H "Content-Type: application/json" \
  -d '{
    "title": "Updated product list"
  }'

An empty JSON object is accepted and leaves the task unchanged:

{}

The title field may be omitted during an update, but explicitly sending "title": null is rejected.

Delete a task

curl -X DELETE "http://127.0.0.1:8000/tasks/1"

The endpoint returns the deleted task.

Validation Rules

• title is required when creating a task.
• Leading and trailing whitespace is removed from title.
• An empty or whitespace-only title is rejected.
• due_date must use the ISO format YYYY-MM-DD.
• description and due_date may be null.
• During partial updates, omitted fields remain unchanged.
• During partial updates, title: null is rejected.

Database

The application uses SQLite.

The database file is stored at:

data/tasks.db

SQLite generates task IDs automatically. Dates are stored as ISO-formatted text, and optional values are stored as SQL NULL.

The database layer is separated from the HTTP layer:

• api.py handles requests, responses, and HTTP errors.
• database.py contains SQL and database operations.
• models.py contains request and response models.

Tests

Run the complete test suite:

pytest -q

The tests cover:

• successful CRUD operations
• missing-task 404 responses
• request validation
• empty and whitespace-only titles
• invalid dates
• title: null during updates
• empty partial updates
• SQLite inserts and reads
• nullable dates
• empty task lists
• reading multiple tasks
• response data integrity

API tests use an isolated SQLite database created inside pytest's tmp_path. The application database is not modified during tests.

Current Scope

This project intentionally uses direct SQLite queries to demonstrate the complete request-to-database flow without hiding it behind an ORM.

Potential future improvements include:

• task completion status
• filtering and pagination
• SQLAlchemy
• PostgreSQL
• database migrations
• Docker
• authentication
• structured logging
• deployment

License

This project is intended for educational and portfolio use.