Python Project — URL Shortener (Flask + SQLite)

What this project does

This mini app takes a long URL (example: https://something.com/very/long/url)
and converts it into a short

when user opens that short URL → it redirects to original URL.

Tech Stack Used

How it works

1. user submits a URL on /
2. server stores it in SQLite table with a short id
3. user receives a shortened link back
4. opening /<short_id> → redirects

Perfect small backend starter project.

Features you can add later

• custom URL slug
• click count analytics
• QR code generation

code

from flask import Flask, request, redirect, jsonify
import sqlite3, string, random

app = Flask(__name__)

# init table on first run
with sqlite3.connect("urls.db") as db:
    db.execute("CREATE TABLE IF NOT EXISTS urls(id TEXT PRIMARY KEY, original TEXT)")

# random short id generator
def generate_id(n=6):
    return "".join(random.choices(string.ascii_letters + string.digits, k=n))

@app.post("/shorten")
def shorten():
    data = request.get_json()
    original = data.get("url")

    short_id = generate_id()
    with sqlite3.connect("urls.db") as db:
        db.execute("INSERT INTO urls(id, original) VALUES(?, ?)", (short_id, original))

    return jsonify({"short_url": f"http://localhost:5000/{short_id}"})


@app.get("/<short_id>")
def redirect_to_original(short_id):
    with sqlite3.connect("urls.db") as db:
        row = db.execute("SELECT original FROM urls WHERE id = ?", (short_id,)).fetchone()

    if row:
        return redirect(row[0])
    return "Not Found", 404


@app.get("/")
def home():
    return """
    <form action="/shorten" method="post" onsubmit="event.preventDefault(); send()">
      <input type="text" id="url" placeholder="Enter URL" style="width:400px"/>
      <button type="submit">Shorten</button>
    </form>
    <script>
      async function send(){
        const url = document.getElementById('url').value;
        const r = await fetch('/shorten', {method:'POST', headers:{'Content-Type':'application/json'}, body:JSON.stringify({url})});
        alert((await r.json()).short_url);
      }
    </script>
    """

if __name__ == "__main__":
    app.run(debug=True)

how to run

pip install flask
python main.py

open it in browser