Bottle Hello World

1 What is Bottle?

Bottle is a lightweight, single-file web framework for Python. It has a built‑in HTTP server, a simple routing system, templating, utilities for cookies, headers, and form data. Think of it as a Swiss Army knife that fits in your pocket—no heavyweight dependencies.

Single‑file framework
Built‑in WSGI server
Routes, request/response helpers, and templating
Great for microservices, API endpoints, and quick demos

Next, we’ll install Bottle and run a tiny app in under a minute.

2 Prerequisites

You’ll need Python 3.8+ and pip installed. Verify your versions:

python --version
pip --version

3 Install Bottle

Install Bottle using pip:

pip install bottle

You’ll see it pull a single wheel—no surprises.

4 Your first app

Create a file named hello.py and paste the code below:

# hello.py
from bottle import Bottle, run

app = Bottle()

@app.route("/")
def hello():
    return "Hello, Bottle!"

if __name__ == "__main__":
    run(app, host="127.0.0.1", port=8080, debug=True)

5 Run the app

Start the server:

python hello.py

Visit http://127.0.0.1:8080/ in your browser. You should see “Hello, Bottle!”

6 Routes and paths

Add a few routes to see patterns in action:

from bottle import Bottle, template

app = Bottle()

@app.route("/")
def index():
    return "Home"

@app.route("/hello/<name>")
def greet(name):
    # Returns an HTML string. No external templating engine required for basics.
    return template("<h1>Hello, !</h1>", name=name)

if __name__ == "__main__":
    # Auto-reload works nicely with debug=True during development.
    app.run(host="127.0.0.1", port=8080, debug=True, reloader=True)

7 Request params and query strings

Bottle passes route params as function arguments and captures query strings with request.query:

from bottle import Bottle, request

app = Bottle()

@app.route("/sum/<a>/<b>")
def add(a, b):
    return f"{a} + {b} = {int(a) + int(b)}"

@app.route("/search")
def search():
    q = request.query.get("q", "")
    return f"Searching for: {q}"

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8080, debug=True)

8 POST, JSON, and status codes

Handle POSTed JSON and set an HTTP status code:

from bottle import Bottle, request, response
import json

app = Bottle()

@app.route("/echo", method="POST")
def echo():
    response.content_type = "application/json"
    response.status = 201
    body = request.json or {}
    return json.dumps({"you_sent": body})

if __name__ == "__main__":
    app.run(host="127.0.0.1", port=8080, debug=True)

9 Static files and a basic template

Serve static assets from a folder and use Bottle’s built‑in SimpleTemplate engine:

# File: app.py
from bottle import Bottle, static_file, template, run

app = Bottle()

# Serve files from ./static
@app.route("/static/<filepath:path>")
def static(filepath):
    return static_file(filepath, root="./static")

@app.route("/")
def index():
    return template("<h1>Hello from .</h1>", title="Bottle")

if __name__ == "__main__":
    run(app, host="127.0.0.1", port=8080, debug=True)

Create templates/index.tpl with content like: <% title = "Index" %> ... then render it with template("index", title="Index") if you prefer files.

10 Testing quickly

Use curl to verify responses without leaving the terminal:

curl http://127.0.0.1:8080/
curl "http://127.0.0.1:8080/hello/World"
curl "http://127.0.0.1:8080/search?q=potato"
curl -X POST http://127.0.0.1:8080/echo -H "Content-Type: application/json" -d '{"msg":"hi"}'

11 Next steps

From here, add error handlers, middleware, and route decorators. Hook up a production server (gunicorn + uvicorn workers) or deploy behind a reverse proxy. Keep it small, keep it fast.

Tutorial Progress