Idfc First Bank

The process consisted of an OA, three technical interviews (L1, L2, L3) and an HR round. The OA covered aptitude, OOPs, code/flowchart-based questions, recursion, SOAP vs REST, and DSA problems. The aptitude section included logical and arithmetic questions, while the technical section tested programming fundamentals and code output. Technical Round 1 focused mainly on Java and CS fundamentals. Questions covered JVM vs JRE, access modifiers, heap and stack memory, lambda functions, exceptions, overloading and other Java concepts. The discussion then moved to OS and Computer Networks, including thrashing, page faults, paging, process scheduling, DNS and CDNs. I was also asked to design a BookMyShow-like database schema, write a query to find the top customer per week, explain window functions such as RANK() and ROW_NUMBER(), and discuss how to prevent simultaneous booking of the same seat using locking. Technical Round 2 was broader and heavily project-oriented. I was asked about IoT, microcontrollers, APIs, the Hugging Face API, TLS and what happens when a website is entered in a browser. I also faced a DSA problem and questions on my Aerosol project, including why spectral clustering was used instead of K-Means. The discussion further covered Kubernetes, DevOps, AWS EC2, cloud concepts, backend, elasticity, CTF/security and recursion/iterators. Technical Round 3 and HR focused on projects, Docker/containerization, namespaces, cgroups, networking, MongoDB vs MySQL, ACID transactions, Node.js, Express, V8 and JIT compilation. The HR round covered my introduction, background, banking experience, relocation, why IDFC, personal improvement areas, app ideas and handling deadlines.