Task API

A tiny CRUD REST API for managing a list of tasks, built with FastAPI. The "database" is just an in-memory Python list, so it resets every time the server restarts — the point of this project is the HTTP layer, not persistence.

It was built stage by stage as a first backend project: hello-world server → info/health endpoints → read → create → update/delete → interactive docs.

Requirements

• Python 3.11+ (developed on 3.14)

Install & run

From the project folder, create a virtual environment, activate it, install the dependencies, and start the server:

python -m venv .venv
source .venv/bin/activate        # Windows: .venv\Scripts\activate
python -m pip install -r requirements.txt
python -m uvicorn main:app --reload

The API is now live at http://localhost:8000, and interactive Swagger docs are at http://localhost:8000/docs.

Once the virtual environment is active you can drop the python -m prefix and just run pip ... and uvicorn ....

Endpoints

Method	Path	Description	Success	Errors
GET	/	API info (name, version, endpoints)	200	—
GET	/health	Liveness check — {"status":"ok"}	200	—
GET	/tasks	List all tasks	200	—
GET	/tasks/{id}	Get one task by id	200	404 if id unknown
POST	/tasks	Create a task from {"title": "…"}	201	400 if title missing/empty
PUT	/tasks/{id}	Update title and/or done	200	404 if id unknown · 400 if body has neither field
DELETE	/tasks/{id}	Delete a task	204	404 if id unknown

Task shape

{ "id": 1, "title": "Read the FastAPI tutorial", "done": true }

Task-level errors (400 and 404 above) come back as { "error": "message" }. Input that isn't valid JSON of the right type — e.g. GET /tasks/abc — is rejected by FastAPI before it reaches the handler and uses FastAPI's default 422 validation shape ({ "detail": [ ... ] }).

Example

$ curl -i http://localhost:8000/tasks/1
HTTP/1.1 200 OK
date: Wed, 02 Sep 2026 17:22:05 GMT
server: uvicorn
content-length: 56
content-type: application/json

{"id":1,"title":"Read the FastAPI tutorial","done":true}

Requesting an unknown id:

$ curl -i http://localhost:8000/tasks/99
HTTP/1.1 404 Not Found
content-type: application/json

{"error":"Task 99 not found"}

Creating a task:

curl -i -X POST http://localhost:8000/tasks \
  -H "Content-Type: application/json" \
  -d '{"title":"Buy milk"}'
# → 201 Created
# {"id":4,"title":"Buy milk","done":false}

Swagger UI

FastAPI generates interactive documentation from the code. Every endpoint is listed with a Try it out button that sends real requests.

Running GET /tasks straight from the docs page:

Project layout

task-api/
├── main.py            # the whole API — routes + in-memory data
├── requirements.txt   # FastAPI + uvicorn
├── docs/              # Swagger UI screenshots
└── README.md