title: node cron jobs on heroku, is using the heroku scheduler necessary?
body: <p>I'm building my app backend as a node/express API to be deployed on Heroku.</p>
  
  <p>I am new to implementing "cron jobs", and I found the npm library named node-cron which seems very straightforward.</p>
  
  <p>Is it as simple as just setting up the cron job in my app runtime code? I know it will not run when the heroku free dyno goes into "sleep mode" (based on other StackOverflow answers), but I plan to use paid dynos in production so that's not an issue.</p>
  
  <p>My main concern is when I "scale up" on heroku and run multiple dynos, will this cause weird interactions? Will every "instance" of my app on a separate dyno try to run its own crons independantly, causing duplication of work?</p>
  
  <p>I know heroku provides a free "scheduler" addon for this to spin up dynos to do this, but if the above won't happen, the scheduler heroku addon seems to be unneeded overhead in my case.</p>
  
  <p>Notes: my cron will be very simple, just doing some database clean up on old records, I didn't want to do it in the database layer to keep things simpler as it seems not super easy to schedule jobs in postgres.</p>
  
  <p>Any insights will be much appreciated. Thank you.</p>