System Design of a hotel reservation system — Part 2

In Part 1, we described the system and the data model for the hotel side of the marketplace. If you haven’t read that already, I would highly recommend you do. The link to Part 1 is here.

System Design of a hotel reservation system — Part 1

System Design of a hotel reservation system — Part 3

Coming to the customer side of the marketplace, the primary functional requirements which we also described in Part 1, are as follows:

1. Search for hotels in a city/geo-location
2. See details of the hotel (room types, charges, availability)
3. Create a reservation
4. Cancel a reservation

Let’s start with the first requirement i.e. the customers must be able to search for a hotel based on a city or geo-location. To enable this, we can use a search engine like Elasticsearch. With elasticsearch, we can make fuzzy queries. Additionally, we can also train a NLP model or use the default model to enable semantic search. We can also run geo_distance queries with elasticsearch. The data will flow into elasticsearch from the “hotels” topic described in Part 1. We can have a lambda (serverless function) that consumes messages from “hotels” topic and adds/updates records in elasticsearch index. Adding elasticsearch to our component diagram, it now looks like this:

The elasticsearch index will store the hotel details as a composite object document, something like:

{
  "name": "ABC",
  "address": "DEF",
  .
  .
  .
  "contact": [
    {
      "type": "PHONE",
      "value": "9876543210"
    }
  ],
  "images": [
    "ImageURL1",
    "ImageURL2"
  ],
  "tags": [
    "5 star",
    "near airport",
    "hygienic"
  ]
}

Now that we have our data ready to be searched, we need a service that exposes the search endpoint. So let’s now get into the client for the customers.

Customers can access the platform either via website or mobile app. We can have a service called hotel-search-service which internally queries the elasticsearch index based on the customer input.

With the new customer-search-service, our component diagram now looks like this:

The customer can enter his/her choice of city and this system in its current state will return a list of hotels with all the required details and image URLs. The clients can then make a call to CDN to download the images to be shown to the customers.

At this point, we have a system that serves as a hotel directory. We will build further on top of this to get a fully working reservation system ready, in the next post. Thanks for reading!