flowchart LR subgraph Server1 A1[curl] end subgraph Server2 A2[curl] end subgraph User1 B1[SSHKeySyncClient] end subgraph User2 B2[SSHKeySyncClient] end subgraph Main Server subgraph SSHKeySyncServer C[API: /add-key] D[API: /get-keys] E[API: /get-ssh-config] F[File: authorized_keys] G[Database: registered servers] end end A1 & A2 <--> D B1 & B2 --> C B1 & B2 <--> E D <--> F C --> F D --> G G --> E A1 ~~~ A2 B1 & B2 ~~~ D