title: Error: connect ECONNREFUSED 127.0.0.1:5432
body: <p>I'm trying to make request to a postgreSQL DB being accessed by a Node + Express server that I've deployed on Heroku. This is the error im getting when running 'heroku logs': Error: connect ECONNREFUSED 127.0.0.1:5432, along with a couple other errors. I'm using axios on the frontend to make request.</p>
  <p>Here is my server.js file:</p>
  <pre><code>// express
  const express = require('express');
  // environment variables
  require('dotenv').config();
  // data base connector
  const db = require('./db');
  // cors
  const cors = require('cors');
  
  // express instance 
  const app = express();
  
  
  // use cors
  app.use(cors());
  
  // attach data to req.body
  app.use(express.json());
  
  // get all articles 
  app.get('/api/v1/articles', async (req, res, next) =&gt; {
  
      try {
  
          // query database
          const results = await db.query('SELECT * FROM articles;');
  
          // send results
          res.status(200).json({
              results: results.rows
          });
  
          // handle error
      } catch (err) {
  
          next(err);
      }
  });
  
  // get individual article 
  app.get('/api/v1/articles/:id', async (req, res, next) =&gt; {
  
      try {
  
          // query database
          const article = await db.query(`SELECT * FROM articles WHERE id = $1;`, [req.params.id]);
  
          // send back data
          res.status(200).json({
              article: article
          });
  
          // handle error
      } catch (err) {
  
          next(err);
      }
  });
  
  // get article's comments
  app.get('/api/v1/articles/:id/comments', async (req, res, next) =&gt; {
  
      try {
  
          // query database
          const comments = await db.query(`SELECT * FROM comments WHERE article_id = $1;`, [req.params.id]);
  
          // send back data
          res.status(200).json({
              comments: comments
          });
  
          // handle error
      } catch (err) {
  
          next(err);
      }
  });
  
  // add comment 
  app.post('/api/v1/articles/:id/comments', async (req, res, next) =&gt; {
  
      try {
  
          // post comment in database
          const comment = await db.query(`INSERT INTO comments (article_id, author, text) 
          VALUES ($1, $2, $3) returning *;`, [req.body.article_id, req.body.author, req.body.text]);
  
          // send comment back
          res.status(201).json({
              comment
          });
  
          // handle error
      } catch (err) {
          
          next(err);
      } 
  })
  
  // listen
  const port = process.env.PORT || 3001;
  
  app.listen(port, () =&gt; {
      console.log(`Server now listening on PORT ${port}`);
  });
  </code></pre>
  <p>I'm supposedly connected to my DB with the pg library, and the Pool gets the credentials from an .env file. I'm able to connect to the DB within pgAdmin and write queries, make tables etc.
  Any help greatly appreciated</p>