call-stack / splitwise

splitwise system design

Splitwise system design

Splitwise is an app for splitting expenses with your friends. It lets you and your friends add various bills and keep track of who owes who, and then it helps you to settle up with each other.

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Setup

• Run docker compose
  docker compose up

This will start 2 container:

• postgres: Port 5432
• webserver: 8080

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Endpoints

• Add user

  • Method: POST, Endpoint: 127.0.0.1:8080/user
  • request body:
    { "name":"vipul", "phone_number":"3139965135", "email_id":"[e-mail]" }
    This will add new user in users table. phone_number and email_id must be unique.

• Add Group

  • Method: POST, Endpoint: 127.0.0.1:8080/group
  • request body \ { "name":"testgroup", "userid":[1, 2, 3] }
    This will create new group. userid contains users belong to the group. Make sure user is present before creating new user.

• Create Expense

  • Method: POST, Endpoint: 127.0.0.1:8080/expense
  • request body \ { "paid_by": 3, "category":"shop", "Amount":1400, "paid_to":[1] }}. This will create new expense in the database. paid_by is the user who paid for the expense and paid_to are the user who are owned to paid_by. paid_to and paid_by are userids.

• Add Group Expense

  • Method: POST, Endpoint: 127.0.0.1:8080/group_expense
  • request body \ { "paid_by":2, "category":"books", "Amount":2400, "gid":1 } This is same as above call instead of mentioning paid_to user we are sending the group using gid. And the expense will be divided among group equally.

• Modify Expense

  • Method: PATCH, Endpoint: 127.0.0.1:8080/expense
  • request body \ { "id":4, "amount":1600 } This will modify the amount of existing expense. Here id is expense id that we got when we created new expense.

• View Expense

  • Method: GET, Endpoint: 127.0.0.1:8080/expense
  • request body \ {"id":1} This will show the expense corresponding to given id.

• Settle Expense

  • Method: POST, Endpoint: 127.0.0.1:8080/settle
  • request body \ {"id":1} This will settle the expense corresponding to given id.

• Summary

  • Method: Get, Endpoint: 127.0.0.1:8080/summary
  • request body \ {"id":1} This will fetch the balance corresponding to given id. Here id is user id that we got when we added the user.

• All Unsettled

  • Method: Get, Endpoint: 127.0.0.1:8080/all_unsettled
  • This will fetch all unsettled expense.