toapi

Turn any website into a JSON API — declaratively.

toapi lets you point at a web page, declare the fields you want with CSS selectors, and get back a clean JSON API. No crawler to babysit, no database to maintain — pages are fetched and parsed on demand, with built‑in caching.

pip install toapi

Requires Python 3.10+.

from htmlparsing import Attr, Text
from toapi import Api, Item

api = Api()


@api.site("https://news.ycombinator.com")
@api.list(".athing")
@api.route("/posts", "/news")
@api.route("/posts?page={page}", "/news?p={page}")
class Post(Item):
    title = Text(".titleline > a")
    url = Attr(".titleline > a", "href")


api.run(host="127.0.0.1", port=5000)

Run it:

python app.py

Then visit http://127.0.0.1:5000/posts and you get:

{
  "Post": [
    {"title": "Mathematicians Crack the Cursed Curve", "url": "https://www.quantamagazine.org/..."},
    {"title": "Stuffing a Tesla Drivetrain into a 1981 Honda Accord", "url": "https://jalopnik.com/..."}
  ]
}

   ┌────────────┐    ┌────────────┐    ┌────────────┐
   │  /posts    │ ─▶ │  fetch     │ ─▶ │  parse     │ ─▶  JSON
   │  (route)   │    │  (cache)   │    │  (Item)    │
   └────────────┘    └────────────┘    └────────────┘

1. Route — @api.route("/posts", "/news") maps your API path to a source URL.
2. Fetch — pages are fetched with requests (or a headless browser if you pass browser=) and cached in memory.
3. Parse — each Item extracts fields with CSS selectors via htmlparsing.
4. Serve — Flask returns the result as JSON; subsequent calls hit the cache.

• Declarative — describe data, not scraping logic.
• Routes — map clean API paths to messy source URLs with {param} placeholders.
• Multi-site — merge several websites behind one API.
• Cleaning hooks — define clean_<field> methods to post-process values.
• Caching — pages and parsed results are cached automatically.
• Headless browser — pass Api(browser="/path/to/geckodriver") for JS-heavy sites.

Add a clean_<fieldname> method on the Item to transform a value before it's returned:

@api.site("https://news.ycombinator.com")
@api.route("/posts", "/news")
class Page(Item):
    next_page = Attr(".morelink", "href")

    def clean_next_page(self, value):
        return f"/posts?{value.split('?', 1)[1]}"

git clone https://github.com/elliotgao2/toapi.git
cd toapi
uv sync          # install deps into .venv
uv run pytest    # run tests
uv run ruff check .

We use uv for packaging and ruff for lint + format. Pre-commit hooks keep both clean:

uv run pre-commit install

Pull requests are welcome. For non-trivial changes, please open an issue first to discuss what you'd like to change. Make sure uv run pytest and uv run ruff check . pass before submitting.

MIT © Elliot Gao