Firebase Cloud Functions throws a DNS error when calling an external API [duplicate]

Question

I am trying to call CoinMarketCap's public API but it always fails with following error:

error occured Error: getaddrinfo ENOTFOUND api.coinmarketcap.com api.coinmarketcap.com:443

When I call the URL from the browser it returns the result instantly. The code is pretty simple:

const functions = require('firebase-functions');
const axios = require('axios');
exports.getBtcPrice = functions.https.onRequest((req, res) => {
    axios.get('https://api.coinmarketcap.com/v1/ticker/bitcoin')
        .then( (response) => {
            console.log(response);
            res.send("data received");
        })
        .catch((error) => {
            console.log(error);
            res.send("error occured "+ error)
        });
});

Answer 1

If you are on the free plan outbound networking with firebase functions only works with google services. They mention this is the cloud function section on the pricing page https://firebase.google.com/pricing/

You have to move to a paid tier if you want to use third-party APIs.