Python Classroom notes 12/May/2026

Designing REST APIs

• A REST API (API) exposes your application as resources. A resource is usually a noun in your business domain.

SuperMarket – Inventory

• Identify possible things or nouns in supermarket inventory

| Business thing/noun | REST Resource |
| ——————- | ————– |
| Product | /products |
| Supplier | /suppliers |
| Store/Branch | /stores |
| purchase order | /purchase-orders |
| Inventory stock | /inventory-items |

• API design starts by asking

what are important things in my system users want to create, read, update or delete

• Examples: In supermarket we need to track
  • Products: rice, milk, shampoo
  • Categories: groceries, dairy, bakery
  • Suppliers: Amul, ITC, local bakery (Iyengars Bakery)
  • Stores: Hyderabad branch, Bangalore Branch, Noida Branch
  • Current Stock quantity
  • Stock coming in & going out
  • Expired/Damaged items

Identifying Main resources

• Product: A product is the master item

{
    "id": 101,
    "name": "Amul Milk 1L",
    "sku": "MILK-AMUL-1L",
    "category-id": 5,
    "unit": "litre",
    "mrp": 75
}

• Operations – Product

GET /products # list all products
GET /products/101 # Give me info about Amul Milk 1 lt
POST /products    # create a product
PUT /products/101  # update
DELETE /products/101 # delete

• /products refers to a collection and /products/101 refers to one item

• Operations – Store

GET /stores
GET /stores/1
POST /stores
DELETE /stores/1

• Data

{
    "id": 1,
    "name": "Hyderabad Main Branch",
    "location": "Ameerpet"

}

Identfying Resources for Redbus – Bus Ticketing platform

• Things
  • Bus Operator
  • Routes
  • Seats
  • Bookings
  • Passengers
  • City
  • Bus
  • Seat
  • Payment

Identifing Resources for Swiggy

• Things:
  • Customer
  • Restaurant
  • Menu
  • Menu Item
  • Delivery Partner
  • Address
  • Coupons
  • Complaint
  • Order
  • Payment
• On each thing what are possible actions
  • Create a customer
  • Update a customer
  • Delete a customer
  • Get all customers
• REST

/customers
  GET /customers  => get all customers
  POST /customers => create
  PUT  /customers => update
  GET /customers/1234 => get specific customer

• API Design is generally done in openapi format

• Exercise:

  • Understand REST APIs of
    • any weather providers
    • any bulk sms provider