currency-converter-python-tutorial — Flask 工具站模板

SHA-256: 2da0b29d4dbdab9a24cf12878f75f5a38e1478c61bd6bbbef2a51b9d66bc3db8

2026-10-01T02:44:20.384Z

# Currency Converter | APIVerve Template

[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
[![Python](https://img.shields.io/badge/Python-3.12-3776AB)](requirements.txt) [![Flask](https://img.shields.io/badge/Flask-3-000000)](app.py)
[![APIVerve | Exchange Rate](https://img.shields.io/badge/APIVerve-Exchange_Rate-purple)](https://apiverve.com/marketplace/exchangerate?utm_source=github&utm_medium=template&utm_campaign=currency-converter-python-tutorial)

Convert an amount between 21 currencies at today’s exchange rate. A web app you can deploy, and a command-line tool.

[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fapiverve%2Fcurrency-converter-python-tutorial&project-name=currency-converter&repository-name=currency-converter&env=APIVERVE_API_KEY&envDescription=Your%20APIVerve%20API%20key.%20Free%20to%20create%2C%20no%20card%20needed.&envLink=https%3A%2F%2Fdashboard.apiverve.com%2Fsignup%3Fapi%3Dexchangerate%26utm_source%3Dvercel%26utm_medium%3Dtemplate%26utm_campaign%3Dcurrency-converter-python-tutorial)

![Currency Converter turning 100 US dollars into euros](https://raw.githubusercontent.com/apiverve/currency-converter-python-tutorial/main/screenshot.png)

---

### Get your free API key

This template needs an APIVerve API key. **[Sign up free](https://dashboard.apiverve.com/signup?api=exchangerate&utm_source=github&utm_medium=template&utm_campaign=currency-converter-python-tutorial)**, no credit card required.

---

## Deploy in one click

Click **Deploy with Vercel** above. Vercel copies this repo to your GitHub account, asks for your `APIVERVE_API_KEY`, and gives you a live URL about a minute later.

## Run it locally

1. **Clone the repository**
   ```bash
   git clone https://github.com/apiverve/currency-converter-python-tutorial.git
   cd currency-converter-python-tutorial
   ```

2. **Install the dependencies**
   ```bash
   python -m venv .venv
   source .venv/bin/activate      # Windows: .venv\Scripts\activate
   pip install -r requirements.txt
   ```

3. **Add your API key**
   ```bash
   cp .env.example .env
   ```
   Then open `.env` and set `APIVERVE_API_KEY`.

4. **Start it**
   ```bash
   python app.py
   ```

5. **Open** `http://localhost:3000`

`python app.py` serves the page and the API route together, so you don't need the Vercel CLI.

## Use it from the command line

```bash
python converter.py 100 USD EUR
```

Run it with no arguments to be prompted instead. It reads the same `.env` as the web app.

## How it works

1. The page (`public/index.html`) calls `GET /api/rate?from=USD&to=EUR`.
2. `app.py` checks both are 3-letter currency codes, then calls Exchange Rate. Your API key stays on the server and never reaches the browser.
3. The page shows the result.

```
├── app.py             # Flask app: the /api/rate route, which holds your key
├── apiverve.py        # Shared by app.py and converter.py: the key, the APIVerve call, the rate limit
├── converter.py       # The command-line version
├── public/            # The page: index.html, app.js, ui.js, style.css
├── requirements.txt   # flask, requests
├── .python-version    # 3.12, for Vercel
└── .env.example       # Copy to .env and add your key
```

### The API call

```python
res = requests.get(
    'https://api.apiverve.com/v1/exchangerate',
    params={'currency1': 'USD', 'currency2': 'EUR'},
    headers={'x-api-key': os.environ['APIVERVE_API_KEY']},
)
data = res.json()['data']
# data['exchangeRate'], data['lastUpdated']
```

Some response fields are for paid plans and come back empty on the free plan. The page shows whatever it gets and leaves the rest out, so it works on every plan.

## Before you share your URL

Once deployed, anyone who finds your URL can use it on your API key. Each visitor can make 10 requests a minute, which is fine for a demo. The limit is kept in memory, so it isn't shared between serverless instances. For production:

- Put the page behind your own sign-in, or
- Move the limit to a shared store such as [Upstash Redis](https://upstash.com/), or
- Call the route only from your own backend.

## Ideas to extend it

- Show prices in the visitor’s currency on a store
- Convert expenses in a travel or accounting app
- Add more currencies: the API accepts any 3-letter code it supports

## API reference

- [Exchange Rate](https://apiverve.com/marketplace/exchangerate?utm_source=github&utm_medium=template&utm_campaign=currency-converter-python-tutorial): `GET https://api.apiverve.com/v1/exchangerate?currency1=&currency2=`
- [Full documentation](https://docs.apiverve.com?utm_source=github&utm_medium=template&utm_campaign=currency-converter-python-tutorial)

## Tech stack

- **Flask** for the API route, with **requests** to call APIVerve (Python 3.12)
- Plain HTML, CSS and JavaScript for the page: no framework and no build step
- Deploys to Vercel as-is: `app.py` becomes a Python function and `public/` is served from the CDN

## License

MIT. See [LICENSE](LICENSE).