There's no right answer to this and really depends on the scale at which you are going to operate. Few general pointers you could follow:

• Running multiple instances of the app (which would require a load-balancer and possibly a reverse-proxy)
• Hardening security (check top 10 OWASP vulnerabilities)
• Using gzip compression for your responses
• Proper logging for Root Cause Analysis of errors (check the ELK stack)
• Using caching servers (like Memcached) for reduced DB calls
• Delegating tasks like session management to in-memory databases (like Redis)

There are a lot of other things I might be missing out here, but this is something that should get you started.

I should also mention that a precursor to all of the above should be setting up solid CICD pipelines and automating everything from building your app to unit-testing, integration testing, code coverage, code quality scans, SAST/DAST scans, deployment, etc.

You should also follow a strict git workflow and protect branches to prevent accidental pushes. Check this guide out.

Hope this helps!

In General before writing code you can draft below plan:

• Overview of you Application : You must have to prepare a good where you can summaries the design, tech stack, type of user, your database architecture , approx number of user you can expect in a month, you app sitemap, functional flow, Justify your version, you offline activity,platform etc. These all entity will help you to scale your app in a good fashion. Even you can break into very small pieces which you can plan to deploy in stage 1 and also same time you can the next level of goal.
• Start Your development : Development is nothing but taking the designed mockups or wire-frame and make them functional. Start writing the code for frontend and backend and always cpalce a standard so you can reuse the code, and build a CMS or API if needed. If you are planning to use any API do a good research and list out the impacts.
• Deploy your application :

• Plan of monitoring : So once we have deploy our application in production and ready with server setup let's look into adding monitoring to improve our awareness of the state of our servers and services. Monitoring software, such as Newrelic, Nagios,.Dynatrace, Icinga, and Zabbix, which provides a a good dashboards and alert system which helps you look back always to your application system which needs your attention as priority. The goal of this is to help you detect issues with your setup, and start fixing them, before your users encounter them.
• Centralized Logging : Logging takes a major place to gather a good number of information about your servers and also helpful when you are trying to identify trends or problems with your application. You can start looking into Elasticsearch (ELK), Kibana, Logstash etc.
• Backup and recovery strategy : Once evey thing is ready we can work on our backup and recovery plan because might be there are such case where we badly need backup or we might need to recover. A recovery plan is a set of documented procedures to recover from potential failures or administration errors within your server setup. A very basic recovery plan for a server failure could consist of the list of steps that you took to perform your initial server deployment, with extra procedures for restoring application data from backups. A better recovery plan might, in addition to good documentation, leverage deployment scripts and configuration management tools, such as Ansible, Chef, or Puppet, to help automate and quicken the recovery process.

Amaan Kulshreshtha I hope this gives you brief overview about your production app plan.

Regards : Md Zaid Imam