Quotes API (Flask + SQLAlchemy)

Below is a full example of a REST API for a quotes app using Flask and SQLAlchemy with marshmallow. It demonstrates a number of features, including:

• Custom validation

• Nesting fields

• Using dump_only=True to specify read-only fields

• Output filtering using the only parameter

• Using @pre_load to preprocess input data.

Using The API

Run the app.

$ uv run examples/flask_example.py

We’ll use the httpie cli to send requests Install it with uv.

$ uv tool install httpie

First we’ll POST some quotes.

$ http POST :5000/quotes/ author="Tim Peters" content="Beautiful is better than ugly."
$ http POST :5000/quotes/ author="Tim Peters" content="Now is better than never."
$ http POST :5000/quotes/ author="Peter Hintjens" content="Simplicity is always better than functionality."

If we provide invalid input data, we get 400 error response. Let’s omit “author” from the input data.

$ http POST :5000/quotes/ content="I have no author"
{
    "author": [
        "Data not provided."
    ]
}

Now we can GET a list of all the quotes.

$ http :5000/quotes/
{
    "quotes": [
        {
            "content": "Beautiful is better than ugly.",
            "id": 1
        },
        {
            "content": "Now is better than never.",
            "id": 2
        },
        {
            "content": "Simplicity is always better than functionality.",
            "id": 3
        }
    ]
}

We can also GET the quotes for a single author.

$ http :5000/authors/1
{
    "author": {
        "first": "Tim",
        "formatted_name": "Peters, Tim",
        "id": 1,
        "last": "Peters"
    },
    "quotes": [
        {
            "content": "Beautiful is better than ugly.",
            "id": 1
        },
        {
            "content": "Now is better than never.",
            "id": 2
        }
    ]
}