How to Design a Hotel Booking System?

My step-by-step approach

This is one of the front-end system design questions I will be working on. Stay tuned for more interview system design questions I did from Great Frontend, or Exponent.

1) Define the functional and non-functional requirements.

Target audience: front-end / full-stack engineer

Rough sketch mockup for front-end to identify common UI components

We can use ReactJs, Redux, and React-query to hold states and fetch data.

Re-usable React Components can be the following:

1. SearchBar
2. FilterBar
3. ImageCarousel
4. StarRatingWidget
5. MapView

2) Define APIs

• GET /hotels: View all hotels by preselected location
• GET /hotels/{hotel_id}: View hotel details
• POST /reservations: Make a hotel reservation
• POST /payments: Make a payment

APIs Requests and Responses

• GET /hotels: can filter by price, room type, amenities, pagination, and sort. Return a list of hotels
• POST /reservations: make a reservation with the guest name once payment is successful

3) Define Data Model

We can build the models below using relational databases like Postgres.

4. Define High-Level System (Iteration 1)

We will build services into microservices. Each microservice calls its database.

• Guest Service which handles information for the logged user
• Inventory Service which shows available hotels
• Reservation Service which handles booking a hotel
• Payment Service: we will be using 3rd party service like Stripe

5) How can we improve and optimize the system?

System Level Optimizations:

• Images can be stored in an S3 bucket which can be cached through CDN
• Cached previous database results before calling the database again
• Cached commonly popular hotels before going to the server
• Cached last viewed hotels

UI Performance Optimizations:

• use React-Query to cache recent API requests from users
• auto pre-fetch content before the next page or image is selected
• support pagination for /GET requests
• load images in different sizes by the viewport. Can fetch smaller size image of the viewport is small for responsive design
• user debounce() when searching to prevent too many requests from fetching
• make of useCallback() and useMemo() in React Components

Finally, save this diagram below👇

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Thank you for reading!