Heuristics
Outsource generic subdomains
When should I build software myself, or buy it off the shelve?
Short description
Sometimes dependencies are so generic that you don’t want to invest time in it and you can either buy them off the shelf or use a SaaS functionality.
You only oursource when there is enough competition in that market
Examples
Payment providers like stripe, paypal etc. Usermanagement, single sign-on like AWS or oath.com
Context
Use these at a strategic level when defining bounded context. When you want to seperate core domains from supporting and generic subdomains