Glossary: Microservices

Host addresses (127.0.0.1, 0.0.0.0)

Also written: 127.0.0.1, 0.0.0.0, localhost

127.0.0.1 (localhost) means "this computer", which is where Flask's development server listens by default. 0.0.0.0 means "listen on all network interfaces", which services in containers need (`--host 0.0.0.0`) so other containers can connect.