Ujjwal kumar

I'm a Backend Software Engineer with deep expertise in distributed systems, concurrency safety, and system design. I specialize in building backends that are fault-tolerant by design not as an afterthought.

My most significant project, Aerixon, is a concurrent emergency dispatch backend built with atomic MongoDB operations, idempotent APIs, exponential backoff retry mechanisms, and end-to-end audit logging engineered specifically to handle race conditions and state inconsistency under concurrent load.

On the competitive programming side, I'm a LeetCode Knight (1910+ rating, Top 4% globally), secured Rank 602 out of 40,000+ participants in the ICPC Huawei Challenge 2025, and consistently place in the top 1–2% in global LeetCode contests.

I've also mentored 70+ students in DSA, focusing not just on problem-solving but on compiler-level thinking memory layout, complexity guarantees, and low-level execution behavior.

My stack: C++, Node.js, Express, MongoDB, REST APIs, JWT, and System Design (HLD + LLD). I'm currently seeking backend or systems engineering roles where reliability and correctness are first-class concerns.