How to do Axios request from Firebase Cloud Function

I experienced the same issue. An HTTP request with axios returns the following error message : TypeError: Converting circular structure to JSON

Here is an explanation of what is going on and how to get around this

You can use the following package : https://github.com/moll/json-stringify-safe

I'm not sure about the consistency of this approach and personally went for request-promise, which is heavier than axios but allows straightforward HTTP requests.

I changed data.ip to response.data.ip and added return before the two res.status(... lines and the deployed cloud function works for me using Axios when I try it.

The code I have is

    const functions = require('firebase-functions');
    const axios = require('axios');
    const cors = require('cors')({ origin: true });

    exports.checkIP = functions.https.onRequest((req, res) => {
      cors(req, res, () => {
        if (req.method !== "GET") {
          return res.status(401).json({
            message: "Not allowed"
          });
        }
    
        return axios.get('https://api.ipify.org?format=json')
          .then(response => {
            console.log(response.data);
            return res.status(200).json({
              message: response.data.ip
            })
          })
          .catch(err => {
            return res.status(500).json({
              error: err
            })
          })
    
      })
    });

When I invoke the function I get back a reply like { "message": "127.168.121.130" }