                         /---\                
                         \___/                
                       /-------\              
                       ---------              
                       Customer               
                            |                 
                         browses              
                            |                 
              +-------------|----------------+
              |      E-Commerce System       |
              |             |                |
              |             v                |
              |    +----------------+        |
              |    |Web Application |        |
              |    |                |        |
              |    +----------------+        |
              |             |                |
              |           calls              |
              |             |                |
              |             v                |
              |      +------------+          |
              |      |API Gateway |          |
              |      |            |          |
              |      +------------+          |
              |       | |      |             |
              |       | |reads/writes        |
              |       | |      |             |
              |       | |      v             |
              |       | |     .------.       |
             processes payments-____-/|      |
              |       | |    |        |      |
              |       | |    |Database|      |
              |       | |    |        |      |
              |       | |     \-____-/       |
              |       | |                    |
              +-------|-|--------------------+
                      | |                     
                +-----+ +-----+               
                |             |               
+---------------|-------------|-------------+ 
|               | external    |             | 
|               |             |             | 
|               v             v             | 
|    +-----------------+ +--------------+   | 
|    |Payment Provider | |Email Service |   | 
|    |                 | |              |   | 
|    +-----------------+ +--------------+   | 
|                                           | 
+-------------------------------------------+ 
