IRCTC provides online ticketing services to the Indian Railways. The scale of this project is truly amazing.
Indian Railways has over 8.5 billion originating passengers every year. That's more than the population of the Earth. On average, every Indian travels more than seven times a year by rail.
With over 13,500 passenger trains operating over 7300 railway stations, the IRCTC system caters to millions of passengers daily. The system is designed to be highly available, easily extensible, and simple to understand.
Basic API Requirements
- The System Receives over 13.3 Million API calls monthly.
- It has over 140 APIs hitting ~500 backend resources.
- These APIs have many consumers, including well-established companies, tourism companies, and startups!
1. The API Ecosystem diagram for Indian Railways
System Design
- IRCTC is a wrapper/aggregator on top of Indian Railways Booking Systems.
- The booking system is managed by the Centre for Railway Information System (CRIS).
- The project name is CONCERT (Country-wide Network for Computerized Enhanced Reservation and Ticketing). It is an Online Transaction Processing System based on a distributed database.
- It has four data centers in New Delhi, Mumbai, Kolkata, and Chennai. All requests are routed to one of these data centers and completed locally, depending on the region assigned to the train.
- A backup data center in Hyderabad(Secunderabad) provides fault tolerance. About two years ago, a fire in Kolkata caused one of their Passenger Reservation Systems to be shut down. Secunderabad took over for nearly four days, resulting in seamless operations.
- The algorithm for seat booking isn't mentioned in any white paper or tender that we could find. Seems like a secret!
Architecture Diagram
2. System Design of CONCERT, the ticketing system behind IRCTC
The Future
Recently, the railways announced their enterprise architecture project called Pravah. It has the following aims:
- Seamless information flow with Railways Partners (like IRCTC!).
- Secure Transactions using IDAM
- Rate Limiting and Throttling
- Standardised APIs for IRCTC
- Mobile Apps Support
This research began 12 months ago after a live class at InterviewReady. We were trying to design a scalable booking system, and IRCTC impressed us all.
Additional statistics:
Indian Railways manages transactions worth ~₹2 lakh crore every year. They have advanced real-time systems for ticketing, tracking, and monitoring trains.
And their work on scalable booking systems affects us all. More than 8 billion rides!
Sources: All information has been collected from publicly available YouTube videos and the Indian Railways website.