Airbnb/Hotel booking

Functional Requirements

Type Service Description
Hotel Manager Onboarding Hotel managers should be able to register and onboard their properties onto the platform.
Property Management Hotel managers should have the ability to update property details, such as:
  • Adding or removing rooms.
  • Changing pricing.
  • Uploading or updating images and descriptions.
Booking Insights Hotel managers should be able to:
  • View all bookings for their property.
  • Access insights into revenue, booking trends, and related analytics.
User Search Properties Users should be able to search for properties in a specific location with customizable filters, including:
  • Price range.
  • Property type (e.g., beachfront, five-star).
  • Other property attributes.
Book Properties Users should be able to book properties directly from the platform.
Manage Bookings Users should have the ability to view and manage their past and upcoming bookings.
Analytics Analytics Enablement The system should be designed to support future analytics, such as:
  • User behavior.
  • Booking trends.
  • Performance metrics for properties.

Non-Functional Requirements

Metric
Target
Latency
The platform must respond quickly to user actions such as search, booking, or updating availability.
Availability
The system should be operational 99.99% of the time, ensuring no major downtime.
Consistency
Users must always see the most accurate and up-to-date availability of hotel rooms.
Scalability
Handle 120,000 concurrent requests
Peak Traffic Handling
10x surge capacity during holiday seasons
High Level System Design:

Scenarios:

Booking Process: Handling Payment and Room Availability
1. Inserting Booking and Decrementing Quantity

When a booking is made:

2. Time-Limited Reservation

The reserved room cannot stay indefinitely:

3. Handling Different Payment Scenarios

There are four possible outcomes after a booking:

4. Redis Key Expiry Caveats

Database Schema

1. Hotels Table

Stores information about hotels.

Table Name: hotels

      Columns:
        - hotel_id: VARCHAR(255) [Primary Key]
        - name: VARCHAR(255)
        - location: VARCHAR(255)
        - rooms: INT
        - available_rooms: INT
        - amenities: JSON
        - manager_id: VARCHAR(255)
        - created_at: TIMESTAMP
        - updated_at: TIMESTAMP
2. Users Table

Stores information about users who use the platform.

Table Name: users

      Columns:
        - user_id: VARCHAR(255) [Primary Key]
        - name: VARCHAR(255)
        - email: VARCHAR(255) [Unique]
        - phone: VARCHAR(15)
        - password_hash: VARCHAR(255)
        - created_at: TIMESTAMP
        - updated_at: TIMESTAMP
3. Bookings Table

Stores booking details for users.

Table Name: bookings

      Columns:
        - booking_id: VARCHAR(255) [Primary Key]
        - hotel_id: VARCHAR(255) [Foreign Key to hotels(hotel_id)]
        - user_id: VARCHAR(255) [Foreign Key to users(user_id)]
        - checkin_date: DATE
        - checkout_date: DATE
        - rooms: INT
        - status: ENUM('BOOKED', 'CANCELLED', 'COMPLETED')
        - total_amount: DECIMAL(10, 2)
        - created_at: TIMESTAMP
        - updated_at: TIMESTAMP
4. Payments Table

Stores payment information for bookings.

Table Name: payments

      Columns:
        - payment_id: VARCHAR(255) [Primary Key]
        - booking_id: VARCHAR(255) [Foreign Key to bookings(booking_id)]
        - amount: DECIMAL(10, 2)
        - payment_method: ENUM('credit_card', 'debit_card', 'paypal')
        - status: ENUM('PENDING', 'SUCCESS', 'FAILED')
        - created_at: TIMESTAMP
        - updated_at: TIMESTAMP
5. ElasticSearch Index

Used for searching hotels based on criteria like location, amenities, and availability.

      Index Name: hotels_index
      Fields:
        - hotel_id: VARCHAR(255)
        - name: VARCHAR(255)
        - location: VARCHAR(255)
        - available_rooms: INT
        - price_per_night: DECIMAL(10, 2)
        - amenities: JSON
6. Cassandra Archival

Stores historical booking data for analysis.

Table Name: bookings_archive

      Columns:
        - booking_id: VARCHAR(255) [Primary Key]
        - hotel_id: VARCHAR(255)
        - user_id: VARCHAR(255)
        - checkin_date: DATE
        - checkout_date: DATE
        - rooms: INT
        - status: ENUM('BOOKED', 'CANCELLED', 'COMPLETED')
        - total_amount: DECIMAL(10, 2)
        - archived_at: TIMESTAMP
7. Kafka Event Log

Logs events for notifications and analytics.

Table Name: kafka_event_log

      Columns:
        - event_id: VARCHAR(255) [Primary Key]
        - event_type: ENUM('BOOKING_CONFIRMED', 'BOOKING_CANCELLED', 'PAYMENT_SUCCESS', 'PAYMENT_FAILED')
        - payload: JSON
        - created_at: TIMESTAMP

API Design

1. Hotel Service
2. Search Service

This service provides APIs to search for available hotels based on criteria such as location, dates, and amenities.

3. Booking Service

This service manages the booking process, including reservation creation, status updates, and cancellations.

4. Payment Service

This service processes payments and communicates success or failure to the booking service.

5. Booking Management Service

This service allows users to view and manage their bookings, including retrieving booking history.

6. Notification Kafka Consumer

This service listens to Kafka events for updates such as booking status changes and sends notifications to users.

7. Archival Kafka Consumer

Manages data archival to Cassandra and Hadoop for historical analysis and storage.