High-level design

flowchart TD

user[user] --> reverse-proxy[reverse-proxy]

reverse-proxy --> user-service-lb{load-balancer}

reverse-proxy --> redirect-service-lb{load-balancer}

user-service-lb --> user-service[user-service] <--> user-db[(user-db)]

user-service --> shortening-service[shortening-service]

redirect-service-lb --> redirect-service[redirect-service]

shortening-service --> url-db-master[(url-db-master)]

redirect-service <--> redirect-cache[redirect-cache]

redirect-service <--> url-db-replica[(url-db-replica)]

url-db-master --> url-db-replica