Create Your First Python Currency Converter

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Dealing with foreign exchange and currency conversion is a common task for developers in fintech. Building a currency converter app with real-time exchange rates can be both practical and educational. This tutorial will guide you through creating a Python-based currency converter using Streamlit and a forex API.

What Is a Currency Converter App?

A currency converter app is a tool that calculates the value of one currency in terms of another. It provides real-time conversions, helping users track fluctuating exchange rates effortlessly.

👉 Learn more about forex APIs

Why Use Streamlit for Your Currency Converter?

Streamlit is an open-source Python library that simplifies building web applications without requiring front-end expertise. It’s ideal for beginners who want to deploy apps quickly.

Key Benefits of Streamlit:

Prerequisites for Building a Currency Converter

To create this app, you’ll need:

  1. A forex API (e.g., TraderMade) for live exchange rates.
  2. Python installed on your system.
  3. Streamlit library (pip install streamlit).

Step-by-Step Guide to Building the App

1. Install Required Libraries

Run this command in your terminal:

pip install streamlit requests

2. Import Libraries and Set Up the API

import streamlit as st
import requests

base_url = "https://marketdata.tradermade.com/api/v1/convert"
api_key = "YOUR_API_KEY"  # Replace with your actual API key

3. Define Currency Conversion Functions

def convert_currency(amount, from_currency, to_currency):
    url = f"{base_url}?api_key={api_key}&from={from_currency}&to={to_currency}&amount={amount}"
    response = requests.get(url)
    if response.status_code == 200:
        rate = response.json()["quote"]
        converted_amount = response.json()["total"]
        return rate, converted_amount
    return None, None

def fetch_supported_currencies():
    url = "https://marketdata.tradermade.com/api/v1/live_currencies_list?api_key=YOUR_API_KEY"
    response = requests.get(url)
    if response.status_code == 200:
        return list(response.json()["available_currencies"].keys())
    return None

4. Build the Streamlit Interface

def currency_converter():
    st.image("tradermade_logo-01.png", width=200)
    amount = st.number_input("Enter amount to convert:", value=100, step=1)
    
    supported_currencies = fetch_supported_currencies()
    if supported_currencies:
        from_currency = st.selectbox("From currency:", supported_currencies, index=19)
        to_currencies = st.multiselect("To currencies:", supported_currencies, default=["USD"])
        
        if st.button("Convert"):
            st.write("Conversion results:")
            for to_currency in to_currencies:
                rate, converted_amount = convert_currency(amount, from_currency, to_currency)
                if rate:
                    st.write(f"{amount} {from_currency} = {converted_amount} {to_currency} (Rate: 1 {from_currency} = {rate} {to_currency})")
                else:
                    st.error("Failed to fetch rates. Check your API key.")

if __name__ == "__main__":
    currency_converter()

5. Run the App

Execute this command in your terminal:

streamlit run currency_converter.py

FAQs About Python Currency Converters

1. How accurate are the exchange rates?

The rates are fetched in real-time from the API provider, ensuring high accuracy.

2. Can I add more currencies?

Yes! Update the supported_currencies list or modify the API endpoint.

3. Is Streamlit free to use?

Absolutely. Streamlit is open-source and free for deployment.

4. How do I deploy this app online?

👉 Deploy with Streamlit Cloud

Conclusion

You’ve just built a functional currency converter app in Python! Customize it further by:

For support, contact the API provider or explore more Python tutorials. Happy coding!


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