Tech Choices

• Ruby on Rails for Web Applications
• Heroku to deploy
• GitHub for source control
• Use Continuous Integration for testing
• Use PostgreSQL database

Development

• Store ISO 8601 compliant time and date
• Monitoring for your server, database
• Self-service for account deletion
• Admin technology to sign in as User
• Canary deployment to percentile of your servers
• Feature flags to individual user, group of users, percentile of users

Emails

• Separate transactional and marketing sender
• Unsubscribe without login
• Confirmed opt-in for marketing mails (GDPR)

Production

• Canary deploy to % of your servers

Finally if your team grows to a point you need to all sorts of data:

• Read replica of your database