Indian Aadhar ID system is one of the world's largest unique digital identity platforms mostly based on Java and commodity hardware.

Tech Stack for enrollment module.

- Java Springboot

- Hadoop HDFS (Storing enrollment packets)

- Apache Solr (Search)

- Mysql

- MongoDB

- RabbitMQ (Message queue)

- Hadoop MapReduce and Pentaho (Analytics)

Key Takeaways from this architecture.

- Define and use APIs for all components

- Embrace open source, eliminate vendor lock-in

- Create a single source of truth

- Build a resilient system

- Security and privacy should be by design

- Scalability can’t be bought, architect for it.