How to use external APIs in Replit

To use external APIs in Replit, you write normal HTTP requests the same way you would in a local project, but you must keep your API keys in Replit Secrets and avoid relying on environment files like .env. You can use fetch (in Node or the browser), axios, or Python’s requests. Replit lets outgoing requests work normally, but you must protect keys, avoid committing them, and be aware that public Repls expose frontend code — so sensitive API keys must stay in backend code only. Once your secrets are set, you just import your HTTP library and make calls as usual.

 

Why This Works in Replit

 

External APIs are just remote servers you ask for data. Replit runs your code on a real Linux environment, so HTTP requests behave the same as on your laptop. The only real differences are:

• You cannot keep secrets in files like .env — they don’t stay private. Use the Replit Secrets sidebar.
• Your frontend code is public if the Repl is public — so never put API keys in React or client-side JS unless the API is meant to be public.
• Some APIs require HTTPS — Replit already gives you an HTTPS URL, so you're safe.
• Long-running jobs or very large requests might hit sandbox limits — keep requests efficient.

 

Step-by-Step: Safely Calling an External API in Replit (Node.js)

 

Below is a complete, real, working example. This calls an external API using fetch in Node.js.

• Open the Secrets panel in Replit.
• Add a key like API\_KEY with your real key.
• Use process.env.API\_KEY inside your Node code.

// index.js
// Example: calling a weather API (dummy URL for illustration)

import fetch from "node-fetch"; // If using Node 18+, global fetch works without this

const apiKey = process.env.API_KEY;          // Reads from Replit Secrets
const city = "London";

async function getWeather() {
  const url = `https://api.example.com/weather?city=${city}&key=${apiKey}`;

  const res = await fetch(url);              // Make the API request
  const data = await res.json();             // Parse the response

  console.log(data);                          // Log result in the Replit console
}

getWeather();

This runs exactly the same as a local Node app — the only Replit-specific part is storing your key in Secrets.

 

Step-by-Step: External API in Python (Replit)

 

Python works the same way — store secrets in Secrets, then read them via os.environ.

# main.py
# Example: calling an external API using Python requests

import os
import requests

api_key = os.environ["API_KEY"]     # Reads value from Replit Secrets
city = "London"

url = f"https://api.example.com/weather?city={city}&key={api_key}"

response = requests.get(url)        # Make the HTTP request
data = response.json()              # Parse JSON response

print(data)

 

Important Replit-Specific Tips

 

• Never expose secrets in frontend code. React, HTML, and client JS are visible to users. Always proxy requests through your Node/Python backend.
• Public Repls cannot hide environment files, so do not create .env expecting it to stay private.
• Multiplayer mode hides secrets automatically from collaborators unless you explicitly share them.
• Keep your Repl awake if the API depends on webhooks. Free Repls may sleep; use Deployments if consistency matters.
• Check API rate limits. It’s easy to hammer an API during testing. Use console logs thoughtfully.

 

Common Mistakes Beginners Make

 

• Storing API keys in code (you’ll leak them instantly).
• Trying to use .env files like in local dev.
• Calling private APIs directly from React code.
• Forgetting to install dependencies like requests or node-fetch.

 

A Good Mental Model

 

Your Repl backend is just a small cloud server. Treat it like any backend: keep secrets server-side, make HTTP calls in backend code, and expose only safe data to the frontend. If you stick to this model, using external APIs in Replit becomes straightforward and reliable.